diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 3dc76fd..cc7595b 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -25,6 +25,8 @@ jobs:
         run: php vendor/bin/phpcs --standard=phpcs.xml
       - name: "Run PHP Unit Test"
         run: php vendor/bin/phpunit --configuration=phpunit.xml
+      - name: "Run Phpstan"
+        run: php vendor/bin/phpstan --configuration=phpstan.neon --memory-limit=256M
   continuous-integration-php82:
     name: "Continuous Integration php8.2"
     runs-on: ubuntu-latest
@@ -45,6 +47,8 @@ jobs:
         run: php vendor/bin/phpcs --standard=phpcs.xml
       - name: "Run PHP Unit Test"
         run: php vendor/bin/phpunit --configuration=phpunit.xml
+      - name: "Run Phpstan"
+        run: php vendor/bin/phpstan --configuration=phpstan.neon --memory-limit=256M
   coding-standards-php83:
     name: "Continuous Integration php8.3"
     runs-on: ubuntu-latest
@@ -65,3 +69,5 @@ jobs:
         run: php vendor/bin/phpcs --standard=phpcs.xml
       - name: "Run PHP Unit Test"
         run: php vendor/bin/phpunit --configuration=phpunit.xml
+      - name: "Run Phpstan"
+        run: php vendor/bin/phpstan --configuration=phpstan.neon --memory-limit=256M
diff --git a/README.md b/README.md
index 7147c57..3e17b28 100644
--- a/README.md
+++ b/README.md
@@ -35,13 +35,13 @@ $resolver = new Resolver($dnsServer, $cache);
  */
 $useCache = true; // default to true
 $timeout = 3.5; // 3.5 seconds
-$response = $resolver->lookup('domainname.ext', 'A', 'IN', $timeout, $useCache);
+$response = $resolver->lookup('domain-name.ext', 'A', 'IN', $timeout, $useCache);
 
 /**
  * Enable Pseudo OPT 
  */
 $resolver->setDnsSec(true);
-$response = $resolver->lookup('domainname.ext', 'A', 'IN');
+$response = $resolver->lookup('domain-name.ext', 'A', 'IN');
 $answers = $response->getAnswers();
 $records = $answers->getRecords();
 // Filter "A" Address Only
@@ -49,7 +49,7 @@ $arrayA = $records->getFilteredType('A');
 
 ```
 
-> IXFR & AXFR not yet implemented
+> IXFR & AXFR aren't fully implemented yet
 
 
 ## Note
diff --git a/src/Abstracts/AbstractDnsServer.php b/src/Abstracts/AbstractDnsServer.php
index e771d44..5231757 100644
--- a/src/Abstracts/AbstractDnsServer.php
+++ b/src/Abstracts/AbstractDnsServer.php
@@ -64,7 +64,7 @@ public function getSecondaryServer(): ?string
     public function getName(): string
     {
         // fallback default class name
-        return $this->name ??= ltrim(strrchr($this::class, '\\'))?:$this::class;
+        return $this->name ??= ltrim(strrchr($this::class, '\\')?:$this::class)?:$this::class;
     }
 
     /**
@@ -97,6 +97,15 @@ public function unserialize(string $data) : void
         $this->__unserialize(unserialize($data));
     }
 
+    /**
+     * @return array{
+     *     identity:string,
+     *     name: string,
+     *     primaryServer: string,
+     *     secondaryServer: ?string,
+     *     port: int,
+     * }
+     */
     public function __serialize(): array
     {
         return [
@@ -111,7 +120,13 @@ public function __serialize(): array
     /**
      * Magic method for unserialize
      *
-     * @param array $data
+     * @param array{
+     *      identity:string,
+     *      name: string,
+     *      primaryServer: string,
+     *      secondaryServer: ?string,
+     *      port: int,
+     *  } $data
      * @return void
      */
     public function __unserialize(array $data): void
diff --git a/src/Abstracts/AbstractResourceRecordType.php b/src/Abstracts/AbstractResourceRecordType.php
index e30a567..29dce6a 100644
--- a/src/Abstracts/AbstractResourceRecordType.php
+++ b/src/Abstracts/AbstractResourceRecordType.php
@@ -10,10 +10,9 @@
 use ArrayAccess\DnsRecord\Interfaces\ResourceRecord\ResourceRecordMetaTypeInterface;
 use ArrayAccess\DnsRecord\Interfaces\ResourceRecord\ResourceRecordQTypeDefinitionInterface;
 use ArrayAccess\DnsRecord\Interfaces\ResourceRecord\ResourceRecordTypeInterface;
-use ArrayAccess\DnsRecord\ResourceRecord\Definitions\QType;
 use ArrayAccess\DnsRecord\Utils\Buffer;
 use ArrayAccess\DnsRecord\Utils\Lookup;
-use function is_string;
+use function is_array;
 use function ord;
 use function serialize;
 use function sprintf;
@@ -47,11 +46,11 @@ abstract class AbstractResourceRecordType implements ResourceRecordTypeInterface
     /**
      * Response type
      *
-     * @var string|ResourceRecordQTypeDefinitionInterface
+     * @var ResourceRecordQTypeDefinitionInterface
      * @see ResourceRecordTypeInterface::getType()
      * @see Lookup::RR_TYPES
      */
-    protected ResourceRecordQTypeDefinitionInterface|string $type;
+    protected ResourceRecordQTypeDefinitionInterface $type;
 
     /**
      * @var ResourceRecordClassInterface
@@ -112,10 +111,6 @@ public function getOffsetPosition(): int
     protected function parseMessage(): void
     {
         $type = static::TYPE;
-        if (!isset($this->type) && is_string($type)) {
-            $this->type = $type;
-        }
-
         $message = $this->message->getMessage();
         $offsetPosition = $this->offsetPosition;
         $this->name   = Buffer::readLabel($message, $offsetPosition);
@@ -125,12 +120,17 @@ protected function parseMessage(): void
                 'Response header length is invalid'
             );
         }
-        [
-            'type' => $type,
-            'class' => $class,
-            'ttl' => $this->ttl,
-            'length' => $this->rdLength,
-        ] = unpack("ntype/nclass/Nttl/nlength", $this->header);
+        $headerArray = unpack("ntype/nclass/Nttl/nlength", $this->header);
+        $this->rdLength = 0;
+        if (is_array($headerArray)) {
+            [
+                'type' => $type,
+                'class' => $class,
+                'ttl' => $this->ttl,
+                'length' => $this->rdLength,
+            ] = $headerArray;
+        }
+
         $this->rData = substr($message, $offsetPosition, $this->rdLength);
         if (strlen($this->rData) !== $this->rdLength) {
             throw new LengthException(
@@ -138,15 +138,14 @@ protected function parseMessage(): void
             );
         }
 
-        $type  = Lookup::resourceType($type);
-        $class = Lookup::resourceClass($class);
-        if (isset($this->type)) {
-            $originType = $this->getType();
-            if ($originType->getName() !== $type->getName()) {
+        $type  = $type ? Lookup::resourceType($type) : null;
+        $class = Lookup::resourceClass($class??'');
+        if (isset($this->type) || !$type) {
+            if ($this->type->getName() !== $type?->getName()) {
                 throw new MalformedDataException(
                     sprintf(
                         'Response type does not match with current object type. object type: [%s] response type: [%s]',
-                        $originType,
+                        $this->type->getName(),
                         $type
                     )
                 );
@@ -165,6 +164,7 @@ protected function parseMessage(): void
      * @param string $message
      * @param int $rdataOffset
      * @noinspection PhpMissingReturnTypeInspection
+     * @phpstan-ignore-next-line
      */
     protected function parseRData(string $message, int $rdataOffset)
     {
@@ -212,11 +212,6 @@ public function getMessage(): PacketMessageInterface
      */
     public function getType(): ResourceRecordQTypeDefinitionInterface
     {
-        if (isset($this->type)) {
-            is_string($this->type) && $this->type = QType::create($this->type);
-            return $this->type;
-        }
-
         return $this->type;
     }
 
@@ -294,7 +289,7 @@ public function __serialize(): array
     /**
      * Magic method for unserialize
      *
-     * @param array $data
+     * @param array{message: PacketMessageInterface, offsetPosition: int} $data
      * @return void
      * @throws MalformedDataException
      */
diff --git a/src/Cache/Adapter/FileCacheAdapter.php b/src/Cache/Adapter/FileCacheAdapter.php
index 3e4d20f..6e6b3db 100644
--- a/src/Cache/Adapter/FileCacheAdapter.php
+++ b/src/Cache/Adapter/FileCacheAdapter.php
@@ -29,6 +29,7 @@
 use function is_dir;
 use function is_file;
 use function is_int;
+use function is_resource;
 use function is_string;
 use function md5;
 use function preg_match;
@@ -38,6 +39,7 @@
 use function restore_error_handler;
 use function serialize;
 use function set_error_handler;
+use function sprintf;
 use function str_replace;
 use function strlen;
 use function substr;
@@ -139,9 +141,10 @@ private function doInit(string $namespace, ?string $directory): void
     {
         $namespace = trim($namespace);
         $namespace = preg_replace('~[^a-z0-9_\-.]~i', '', $namespace);
-        if ($namespace === '') {
+        if (!$namespace || !is_string($namespace)) {
             $namespace = '@';
         }
+
         if (!$directory
             || trim($directory) === ''
             || trim(trim($directory), '/\\') === ''
@@ -187,12 +190,17 @@ private static function isOpcacheSupport(): bool
             );
     }
 
+    /**
+     * @param string $directory
+     * @param bool $loopDir
+     * @return Generator<string, string>
+     */
     private function scanFiles(string $directory, bool $loopDir = false) : Generator
     {
         if (!is_dir($directory)) {
             return '';
         }
-        $directory = rtrim(realpath($directory)??$directory, '\\/');
+        $directory = rtrim(realpath($directory)?:$directory, '\\/');
         $chars = '+-ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
         $length = strlen($chars);
         for ($i = 0; $i < $length; ++$i) {
@@ -235,9 +243,12 @@ public function prune(): bool
             }
             $value = null;
             $valid = $this->validatePartialFile($file);
+            if (!$valid) {
+                $this->doUnlink($file);
+                continue;
+            }
             try {
-                if ($valid
-                    && is_array(($expiresAt = include $file))
+                if (is_array(($expiresAt = include $file))
                     && count($expiresAt) === 3
                     && is_int($expiresAt[0]??null)
                     && is_string($expiresAt[1]??null)
@@ -285,7 +296,7 @@ private function clearLocalCache(): void
         }
         if (count($this->files) > $maximum) {
             while (count($this->files) > $max) {
-                array_shift(self::$cachesExpires);
+                array_shift($this->files);
             }
         }
     }
@@ -359,7 +370,14 @@ private function write(string $file, string $data) : bool
                 $tmp = $this->generateTempFile();
                 $h = fopen($tmp, 'x');
             }
-
+            if (!is_resource($h)) {
+                throw new Exception(
+                    sprintf(
+                        'Canot create resource from file : %s',
+                        $tmp
+                    )
+                );
+            }
             fwrite($h, $data);
             fclose($h);
             $unlink = true;
@@ -426,7 +444,7 @@ private function doDelete(string $id, string ...$ids) : bool
         return $this->doIdDelete(...$arrayId);
     }
 
-    private function doUnlink(string $file)
+    private function doUnlink(string $file) : bool
     {
         if (self::isOpcacheSupport()) {
             Caller::call('opcache_invalidate', $file, true);
@@ -508,7 +526,7 @@ private function doFetch(string $key): ?CacheDataInterface
             $unlink = true;
             return null;
         } finally {
-            if ($unlink && file_exists($file)) {
+            if ($unlink) {
                 self::$cachesExpires[$file] = 0;
                 unset($this->values[$key]);
                 $this->doUnlink($file);
@@ -559,7 +577,7 @@ public function getItem(string $key): CacheDataInterface
         if (isset($this->values[$key])) {
             return $this->values[$key];
         }
-        return $this->doFetch($key)??(new CacheData($key))->expiresAt(
+        return $this->doFetch($key)??(new CacheData($key))->expiresAfter(
             $this->defaultLifetime === 0
                 ? null
                 : $this->defaultLifetime
diff --git a/src/Cache/Adapter/Psr6CacheAdapter.php b/src/Cache/Adapter/Psr6CacheAdapter.php
index 18701de..4cea758 100644
--- a/src/Cache/Adapter/Psr6CacheAdapter.php
+++ b/src/Cache/Adapter/Psr6CacheAdapter.php
@@ -60,7 +60,7 @@ public function saveItem(CacheDataInterface $cacheData): bool
         $item
             ->set($cacheData)
             ->expiresAfter($cacheData->getExpiresAfter());
-        return $this->getCacheItemPool()->save($item);
+        return $this->getCacheItemPool()?->save($item)??false;
     }
 
     /**
@@ -95,7 +95,7 @@ public function deleteItems(string ...$keys): bool
     public function getItem(string $key): CacheDataInterface
     {
         $cacheItem = $this->getCacheItem($key);
-        $cacheItem = $cacheItem->get();
+        $cacheItem = $cacheItem?->get();
         if ($cacheItem instanceof CacheDataInterface) {
             return $cacheItem;
         }
diff --git a/src/Cache/CacheData.php b/src/Cache/CacheData.php
index 15659bb..934534f 100644
--- a/src/Cache/CacheData.php
+++ b/src/Cache/CacheData.php
@@ -3,12 +3,9 @@
 
 namespace ArrayAccess\DnsRecord\Cache;
 
-use ArrayAccess\DnsRecord\Exceptions\CacheException;
 use ArrayAccess\DnsRecord\Interfaces\Cache\CacheDataInterface;
 use DateInterval;
 use DateTimeInterface;
-use function is_array;
-use function is_string;
 use function serialize;
 use function unserialize;
 
@@ -121,23 +118,20 @@ public function serialize(): string
 
     /**
      * @inheritdoc
-     * @throws CacheException
      */
     public function unserialize(string $data): void
     {
-        $data = unserialize($data);
-        if (!is_array($data) || !is_string($data['key']??null)) {
-            throw new CacheException(
-                'Invalid serialized data'
-            );
-        }
-        $this->__unserialize($data);
+        $this->__unserialize(unserialize($data));
     }
 
     /**
      * Magic method for unserialize
      *
-     * @param array $data
+     * @param array{
+     *     key: string,
+     *     data: mixed,
+     *     ttl: ?int
+     * } $data
      * @return void
      */
     public function __unserialize(array $data): void
@@ -150,7 +144,7 @@ public function __unserialize(array $data): void
     /**
      * Magic method for serializing
      *
-     * @return array{key: string, data: mixed, ttl:int}
+     * @return array{key: string, data: mixed, ttl: ?int}
      */
     public function __serialize(): array
     {
diff --git a/src/DnsServer/CustomDnsServer.php b/src/DnsServer/CustomDnsServer.php
index 0433303..c3804b8 100644
--- a/src/DnsServer/CustomDnsServer.php
+++ b/src/DnsServer/CustomDnsServer.php
@@ -10,7 +10,7 @@
 /**
  * User defined dns server
  */
-class CustomDnsServer extends AbstractDnsServer
+final class CustomDnsServer extends AbstractDnsServer
 {
     use DisableSetterTrait;
 
diff --git a/src/DnsServerStorage.php b/src/DnsServerStorage.php
index c5cf51f..563e0fd 100644
--- a/src/DnsServerStorage.php
+++ b/src/DnsServerStorage.php
@@ -32,12 +32,12 @@ class DnsServerStorage implements DnsServerStorageInterface
     ];
 
     /**
-     * @var array<string, DnsServerInterface>
+     * @var DnsServerInterface[]
      */
     protected array $servers = [];
 
     /**
-     * @var array<class-string, DnsServerInterface>
+     * @var array<DnsServerInterface|class-string<DnsServerInterface>>
      */
     private static array $cachedDefaultServers = [];
 
@@ -79,13 +79,19 @@ public static function createDefault() : static
     {
         $obj = null;
         foreach (self::DEFAULT_SERVER as $className) {
+            $server = self::getDefaultServer($className);
+            if (!$server) {
+                continue;
+            }
             if (!$obj) {
-                $obj = new static(self::getDefaultServer($className));
+                $obj = new static($server);
                 continue;
             }
-            $obj->add(self::getDefaultServer($className));
+            $obj->add($server);
         }
-
+        /**
+         * @var static $obj
+         */
         return $obj;
     }
 
@@ -168,7 +174,7 @@ public function __serialize(): array
     /**
      * Magic method unserialize
      *
-     * @param array $data
+     * @param array{servers: DnsServerInterface[]} $data
      * @return void
      */
     public function __unserialize(array $data): void
diff --git a/src/Interfaces/Cache/CacheStorageInterface.php b/src/Interfaces/Cache/CacheStorageInterface.php
index ce272a6..989059c 100644
--- a/src/Interfaces/Cache/CacheStorageInterface.php
+++ b/src/Interfaces/Cache/CacheStorageInterface.php
@@ -30,6 +30,7 @@ public function getAdapter() : ?CacheAdapterInterface;
      * Set cache adapter
      *
      * @param CacheAdapterInterface $cacheAdapter
+     * @phpstan-ignore-next-line
      */
     public function setAdapter(CacheAdapterInterface $cacheAdapter);
 
diff --git a/src/Interfaces/DnsServer/DnsServerStorageInterface.php b/src/Interfaces/DnsServer/DnsServerStorageInterface.php
index 759ffe2..443a1c6 100644
--- a/src/Interfaces/DnsServer/DnsServerStorageInterface.php
+++ b/src/Interfaces/DnsServer/DnsServerStorageInterface.php
@@ -29,6 +29,7 @@ public static function createDefault() : static;
      * Append dns server into collections
      *
      * @param DnsServerInterface $server
+     * @phpstan-ignore-next-line
      */
     public function add(DnsServerInterface $server);
 
@@ -36,6 +37,7 @@ public function add(DnsServerInterface $server);
      * Remove dns server
      *
      * @param DnsServerInterface|string $server
+     * @phpstan-ignore-next-line
      */
     public function remove(DnsServerInterface|string $server);
 
@@ -55,7 +57,7 @@ public function get(DnsServerInterface|string $server): ?DnsServerInterface;
     public function getServers(): array;
 
     /**
-     * @return Traversable<DnsServerInterface>
+     * @return Traversable<string, DnsServerInterface>
      */
     public function getIterator() : Traversable;
 }
diff --git a/src/Interfaces/Packet/PacketHeaderInterface.php b/src/Interfaces/Packet/PacketHeaderInterface.php
index 0f931aa..90e9826 100644
--- a/src/Interfaces/Packet/PacketHeaderInterface.php
+++ b/src/Interfaces/Packet/PacketHeaderInterface.php
@@ -37,9 +37,9 @@ interface PacketHeaderInterface extends Serializable
      * Create a new Header object from given raw data
      *
      * @param PacketMessageInterface|string $message the raw message from dns response
-     * @return static
+     * @return PacketHeaderInterface
      */
-    public static function fromMessage(PacketMessageInterface|string $message): static;
+    public static function fromMessage(PacketMessageInterface|string $message): PacketHeaderInterface;
 
     /**
      * Crate query header for request dns server
@@ -81,7 +81,7 @@ public function getId(): int;
      * A one-bit field that specifies whether this message is a
      *  query (0), or a response (1)
      *
-     * @return int<0|1>
+     * @return int Lookup::QR_RESPONSE|Lookup::QR_QUERY
      */
     public function getQR(): int;
 
diff --git a/src/Interfaces/Packet/PacketQuestionInterface.php b/src/Interfaces/Packet/PacketQuestionInterface.php
index 434f4c1..8309513 100644
--- a/src/Interfaces/Packet/PacketQuestionInterface.php
+++ b/src/Interfaces/Packet/PacketQuestionInterface.php
@@ -14,12 +14,12 @@ interface PacketQuestionInterface extends Serializable
      * Question constructor
      *
      * @param string $name QNAME / Name
-     * @param string|Int|ResourceRecordTypeInterface $type QTYPE / Type
+     * @param string|Int|ResourceRecordTypeInterface|ResourceRecordQTypeDefinitionInterface $type QTYPE / Type
      * @param string|int|ResourceRecordClassInterface $class QCLASS / Class
      */
     public function __construct(
         string $name,
-        string|Int|ResourceRecordTypeInterface $type,
+        string|Int|ResourceRecordTypeInterface|ResourceRecordQTypeDefinitionInterface $type,
         string|int|ResourceRecordClassInterface $class
     );
 
diff --git a/src/Interfaces/Packet/PacketResourceRecordsInterface.php b/src/Interfaces/Packet/PacketResourceRecordsInterface.php
index 6e9d0e2..c12a658 100644
--- a/src/Interfaces/Packet/PacketResourceRecordsInterface.php
+++ b/src/Interfaces/Packet/PacketResourceRecordsInterface.php
@@ -20,6 +20,7 @@ interface PacketResourceRecordsInterface extends IteratorAggregate, Countable, S
      * Add record
      *
      * @param ResourceRecordTypeInterface $record
+     * @phpstan-ignore-next-line
      */
     public function add(ResourceRecordTypeInterface $record);
 
@@ -27,6 +28,7 @@ public function add(ResourceRecordTypeInterface $record);
      * Remove record
      *
      * @param ResourceRecordTypeInterface $record
+     * @phpstan-ignore-next-line
      */
     public function remove(ResourceRecordTypeInterface $record);
 
@@ -42,19 +44,20 @@ public function getRecords(): array;
      *
      * @param string $type
      * @param bool $single
-     * @return array|ResourceRecordTypeInterface|null
+     * @return array<ResourceRecordTypeInterface>|ResourceRecordTypeInterface|null
      */
     public function getFilteredType(string $type, bool $single = false) : null|array|ResourceRecordTypeInterface;
 
     /**
      * Return array records
+     *
      * @uses ResourceRecordTypeInterface::toArray()
-     * @return array<array>
+     * @return array<array<ResourceRecordTypeInterface>>
      */
     public function toArray() : array;
 
     /**
-     * @return Traversable<ResourceRecordTypeInterface>
+     * @return Traversable<string, ResourceRecordTypeInterface>
      */
     public function getIterator(): Traversable;
 }
diff --git a/src/Interfaces/Packet/PacketResponseInterface.php b/src/Interfaces/Packet/PacketResponseInterface.php
index b89e15e..f72eaea 100644
--- a/src/Interfaces/Packet/PacketResponseInterface.php
+++ b/src/Interfaces/Packet/PacketResponseInterface.php
@@ -22,7 +22,7 @@ public function getPacketData() : PacketRequestDataInterface;
     /**
      * Get used protocol
      *
-     * @return string<"udp"|"tcp">
+     * @return string udp or tcp
      */
     public function getProtocol() : string;
 
@@ -64,7 +64,7 @@ public function getAnswers() : PacketAnswersInterface;
     public function getStartTime() : float;
 
     /**
-     * Get end of query time
+     * Get the end of query time
      *
      * @return float
      */
diff --git a/src/Interfaces/ResourceRecord/ResourceRecordTypeInterface.php b/src/Interfaces/ResourceRecord/ResourceRecordTypeInterface.php
index 56cee37..4546aee 100644
--- a/src/Interfaces/ResourceRecord/ResourceRecordTypeInterface.php
+++ b/src/Interfaces/ResourceRecord/ResourceRecordTypeInterface.php
@@ -121,6 +121,7 @@ public function getRDLength() : int;
 
     /**
      * Resource data
+     * @phpstan-ignore-next-line
      */
     public function getValue();
 
@@ -141,7 +142,7 @@ public function getQueryMessage() : string;
     /**
      * Return array data
      *
-     * @return array like dns_get_record()
+     * @return array<string, mixed> like dns_get_record()
      * @see \dns_get_record()
      */
     public function toArray() : array;
diff --git a/src/Packet/Answers.php b/src/Packet/Answers.php
index 5486039..36a717e 100644
--- a/src/Packet/Answers.php
+++ b/src/Packet/Answers.php
@@ -110,6 +110,7 @@ private function parseHeader(): PacketHeaderInterface
      * Parse the response question
      *
      * @throws MalformedDataException
+     * @return PacketQuestionInterface[]
      */
     private function parseQuestions() : array
     {
@@ -155,9 +156,10 @@ private function parseQuestions() : array
     /**
      * Parse the records
      *
+     * @return PacketResourceRecordsInterface
      * @throws MalformedDataException
      */
-    private function parseRecords() : Records
+    private function parseRecords() : PacketResourceRecordsInterface
     {
         if (isset($this->records)) {
             return $this->records;
@@ -308,7 +310,7 @@ public function unserialize(string $data): void
     /**
      * Magic method for serializing
      *
-     * @return array{message: Message}
+     * @return array{message: PacketMessageInterface}
      */
     public function __serialize(): array
     {
@@ -318,7 +320,7 @@ public function __serialize(): array
     /**
      * Magic method for unserialize
      *
-     * @param array $data
+     * @param array{message: PacketMessageInterface} $data
      * @return void
      */
     public function __unserialize(array $data): void
diff --git a/src/Packet/Header.php b/src/Packet/Header.php
index c3acf4c..8629f15 100644
--- a/src/Packet/Header.php
+++ b/src/Packet/Header.php
@@ -203,7 +203,7 @@ public function __toString(): string
      * Parse the message
      *
      * @param string $message
-     * @return $this
+     * @return static
      */
     private function parseMessage(string $message) : static
     {
@@ -251,7 +251,7 @@ private function parseMessage(string $message) : static
     /**
      * @inheritdoc
      */
-    public static function fromMessage(PacketMessageInterface|string $message): static
+    public static function fromMessage(PacketMessageInterface|string $message): PacketHeaderInterface
     {
         if (!is_string($message)) {
             $message = $message->getMessage();
@@ -555,6 +555,7 @@ public function serialize(): string
     /**
      * @inheritdoc
      * @return void
+     * @throws \Exception
      */
     public function unserialize(string $data): void
     {
@@ -575,8 +576,9 @@ public function __serialize(): array
     /**
      * Magic method for unserialize
      *
-     * @param array $data
+     * @param array{message: string} $data
      * @return void
+     * @throws \Exception
      * @uses base64_decode() decode to raw data
      */
     public function __unserialize(array $data): void
diff --git a/src/Packet/Message.php b/src/Packet/Message.php
index 6b47caa..4ca5dcc 100644
--- a/src/Packet/Message.php
+++ b/src/Packet/Message.php
@@ -64,7 +64,7 @@ public function __serialize(): array
     /**
      * Magic method for unserialize
      *
-     * @param array $data
+     * @param array{message: string} $data
      * @return void
      * @uses base64_decode() decode to raw data
      */
diff --git a/src/Packet/Question.php b/src/Packet/Question.php
index dc46899..5db8c50 100644
--- a/src/Packet/Question.php
+++ b/src/Packet/Question.php
@@ -42,24 +42,24 @@ class Question implements PacketQuestionInterface
      * @see PacketQuestionInterface::getName()
      * @var string
      */
-    public readonly string $name;
+    private string $name;
 
     /**
      * @see PacketQuestionInterface::getMessage()
      * @var string
      */
-    public readonly string $message;
+    private string $message;
 
     /**
      * @see PacketQuestionInterface::getType()
      */
-    public readonly ?ResourceRecordQTypeDefinitionInterface $type;
+    private ?ResourceRecordQTypeDefinitionInterface $type;
 
     /**
      * @see PacketQuestionInterface::getClass()
      * @var ?ResourceRecordClassInterface
      */
-    public readonly ?ResourceRecordClassInterface $class;
+    private ?ResourceRecordClassInterface $class;
 
     /**
      * @inheritdoc
@@ -103,7 +103,9 @@ private function initName(string $name, bool $internal = false): void
         }
 
         $name = strtolower($name);
-        if (($this->type??null) === 'PTR' && !preg_match('~\.(in-addr|ip6)\.arpa$~', $name)) {
+        if ($this->getType()?->getName() === 'PTR'
+            && !preg_match('~\.(in-addr|ip6)\.arpa$~', $name)
+        ) {
             $name = Addresses::reverseIp($name)??$name;
         }
         $this->name = $name;
@@ -178,14 +180,18 @@ public function unserialize(string $data): void
     /**
      * Magic method for serializing
      *
-     * @return array{name:string, type:string, class:string}
+     * @return array{
+     *     name: string,
+     *     type: string,
+     *     class: string
+     * }
      */
     public function __serialize(): array
     {
         return [
             'name' => $this->name,
-            'type' => $this->type,
-            'class' => $this->class,
+            'type' => $this->getType()?->getName()??'',
+            'class' => $this->getClass()?->getName()??'',
         ];
     }
 
@@ -224,7 +230,11 @@ public static function fromFilteredResponse(
     /**
      * Magic method for unserialize
      *
-     * @param array $data
+     * @param array{
+     *      name: string,
+     *      type: string,
+     *      class: string
+     *  } $data
      * @return void
      */
     public function __unserialize(array $data): void
diff --git a/src/Packet/Records.php b/src/Packet/Records.php
index 8a0916f..4b0e355 100644
--- a/src/Packet/Records.php
+++ b/src/Packet/Records.php
@@ -112,11 +112,17 @@ public function count(): int
         return count($this->records);
     }
 
+    /**
+     * @inheritdoc
+     */
     public function serialize() : string
     {
         return serialize($this->__serialize());
     }
 
+    /**
+     * @inheritdoc
+     */
     public function unserialize(string $data): void
     {
         $this->__unserialize(unserialize($data));
@@ -137,11 +143,14 @@ public function __serialize(): array
     /**
      * Magic method for unserialize
      *
-     * @param array $data
+     * @param array{records: ResourceRecordTypeInterface[]} $data
      * @return void
      */
     public function __unserialize(array $data): void
     {
-        $this->records = $data['records'];
+        $this->records = [];
+        foreach ($data['records'] as $record) {
+            $this->add($record);
+        }
     }
 }
diff --git a/src/Packet/RequestData.php b/src/Packet/RequestData.php
index 3f08be5..2bc8d92 100644
--- a/src/Packet/RequestData.php
+++ b/src/Packet/RequestData.php
@@ -16,6 +16,9 @@
 class RequestData implements PacketRequestDataInterface
 {
 
+    /**
+     * @var PacketQuestionInterface[]
+     */
     protected array $questions;
 
     protected PacketResourceRecordsInterface $additionalRecords;
@@ -73,7 +76,7 @@ public function getQuestions(): array
      */
     public function getQuestion(): PacketQuestionInterface
     {
-        return reset($this->questions);
+        return $this->getQuestions()[0];
     }
 
     /**
@@ -193,7 +196,12 @@ public function unserialize(string $data): void
     /**
      * Magic method for serializing
      *
-     * @return array
+     * @return array{
+     *      questions: PacketQuestionInterface[],
+     *      additionalRecords: PacketResourceRecordsInterface,
+     *      authorityRecords: PacketResourceRecordsInterface,
+     *      answerRecords: PacketResourceRecordsInterface
+     * }
      */
     public function __serialize(): array
     {
@@ -208,7 +216,12 @@ public function __serialize(): array
     /**
      * Magic method for unserialize
      *
-     * @param array $data
+     * @param array{
+     *       questions: PacketQuestionInterface[],
+     *       additionalRecords: PacketResourceRecordsInterface,
+     *       authorityRecords: PacketResourceRecordsInterface,
+     *       answerRecords: PacketResourceRecordsInterface
+     *  } $data
      * @return void
      */
     public function __unserialize(array $data): void
diff --git a/src/Packet/RequestDataWrapper.php b/src/Packet/RequestDataWrapper.php
index 67ad138..bff2d09 100644
--- a/src/Packet/RequestDataWrapper.php
+++ b/src/Packet/RequestDataWrapper.php
@@ -28,7 +28,7 @@ public function getHeader(): PacketHeaderInterface
         return $this->packetRequestData->getHeader();
     }
 
-    public function withHeader(PacketHeaderInterface $header): static
+    public function withHeader(PacketHeaderInterface $header): RequestDataWrapper
     {
         return new self($this->packetRequestData->withHeader($header));
     }
@@ -123,7 +123,7 @@ public function __serialize(): array
     /**
      * Magic method unserialize
      *
-     * @param array $data
+     * @param array{packetRequestData: PacketRequestDataInterface} $data
      * @return void
      */
     public function __unserialize(array $data): void
diff --git a/src/Packet/Response.php b/src/Packet/Response.php
index 48f6473..69dbda8 100644
--- a/src/Packet/Response.php
+++ b/src/Packet/Response.php
@@ -81,6 +81,18 @@ public function unserialize(string $data): void
         $this->__unserialize(unserialize($data));
     }
 
+    /**
+     * @return array{
+     *     startTime: float,
+     *     endTime: float,
+     *     protocol: string,
+     *     server: string,
+     *     port: int,
+     *     packetData: PacketRequestDataInterface,
+     *     answers: PacketAnswersInterface,
+     *     time: int
+     * }
+     */
     public function __serialize(): array
     {
         return [
@@ -98,7 +110,16 @@ public function __serialize(): array
     /**
      * Magic method for unserialize
      *
-     * @param array $data
+     * @param array{
+     *      startTime: float,
+     *      endTime: float,
+     *      protocol: string,
+     *      server: string,
+     *      port: int,
+     *      packetData: PacketRequestDataInterface,
+     *      answers: PacketAnswersInterface,
+     *      time: int
+     *  } $data
      * @return void
      */
     public function __unserialize(array $data): void
diff --git a/src/Resolver.php b/src/Resolver.php
index 195192f..909a69e 100644
--- a/src/Resolver.php
+++ b/src/Resolver.php
@@ -40,9 +40,9 @@ class Resolver
     protected bool $dnsSec = false;
 
     /**
-     * if we should set the recursion desired bit to 1 or 0.
+     * The recursion desired bit to 1 or 0.
      *
-     * by default, this is set to true, the DNS server to perform a recursive
+     * By default, this is set to true, the DNS server to perform a recursive
      * request. If set to false, the RD bit will be set to 0, and the server will
      * not perform recursion on the request.
      */
@@ -96,10 +96,7 @@ public function setRecurse(bool $recurse): void
 
     public function getCache(): CacheStorageInterface
     {
-        if (!isset($this->cache)) {
-            $this->setCache(new CacheStorage());
-        }
-        return $this->cache;
+        return $this->cache ??= new CacheStorage();
     }
 
     public function setCache(CacheStorageInterface $cache): void
@@ -109,10 +106,7 @@ public function setCache(CacheStorageInterface $cache): void
 
     public function getDnsServerStorage(): DnsServerStorage
     {
-        if (!isset($this->dnsServerStorage)) {
-            $this->setDnsServerStorage(DnsServerStorage::createDefault());
-        }
-        return $this->dnsServerStorage;
+        return $this->dnsServerStorage ??= DnsServerStorage::createDefault();
     }
 
     public function setDnsServerStorage(DnsServerStorage $dnsServerStorage): void
@@ -176,7 +170,7 @@ public function createQueryOpcode(
         if ($isOpt || $dnsSec) {
             $requestData
                 ->getAdditionalRecords()
-                ->add(OPT::create($question->getType()->getValue()));
+                ->add(OPT::create($question->getType()?->getValue()??0));
         }
         return $requestData;
     }
@@ -201,6 +195,8 @@ public function query(
             $class,
             $this->isAdFlag(),
             $this->isCdFlag(),
+            $this->isDnsSec(),
+            $this->isRecurse(),
             ...$server
         );
     }
@@ -225,6 +221,8 @@ public function iQuery(
             $class,
             $this->isAdFlag(),
             $this->isCdFlag(),
+            $this->isDnsSec(),
+            $this->isRecurse(),
             ...$server
         );
     }
@@ -269,7 +267,7 @@ public function lookups(
         $udp = null;
         $cached = [];
         foreach ($requests as $key => $request) {
-            $name = $request->getQuestion()->getClass()->getName();
+            $name = $request->getQuestion()->getClass()?->getName()??IN::NAME;
             if (isset($cached[$name])) {
                 $requests[$key] = $cached[$name];
                 continue;
@@ -291,6 +289,10 @@ public function lookups(
                     ] = $this->createSocket($dns, false);
                 }
 
+                /**
+                 * @var resource $socket
+                 * @var string $server
+                 */
                 $socket = $isUdp ? $udp : $tcp;
                 $server = $isUdp ? $udpServer : $tcpServer;
                 $port = $isUdp ? $udpPort : $tcpPort;
@@ -326,8 +328,8 @@ public function lookups(
                     $startTime,
                     $this->createMicrotime(),
                     $protocol,
-                    $server,
-                    $port,
+                    (string) $server,
+                    (int) $port,
                     $request,
                     new Answers($message)
                 );
@@ -343,6 +345,9 @@ public function lookups(
         $this->closeSocketResource($tcp);
         $this->closeSocketResource($udp);
 
+        /**
+         * @var array<Throwable|PacketResponseInterface> $requests
+         */
         return $requests;
     }
 
diff --git a/src/ResourceRecord/Definitions/QType.php b/src/ResourceRecord/Definitions/QType.php
index 6c2ce51..845f370 100644
--- a/src/ResourceRecord/Definitions/QType.php
+++ b/src/ResourceRecord/Definitions/QType.php
@@ -17,6 +17,9 @@ final class QType implements ResourceRecordQTypeDefinitionInterface
 {
     use NamedValueTrait;
 
+    /**
+     * @var array<int, QType>
+     */
     private static array $cachedObject = [];
 
     private function __construct(string $name, int $value)
@@ -27,10 +30,10 @@ private function __construct(string $name, int $value)
 
     /**
      * @param int|string $key
-     * @return self
+     * @return QType
      * @throws InvalidArgumentException
      */
-    public static function create(int|string $key) : self
+    public static function create(int|string $key) : QType
     {
         if (is_string($key)) {
             $key = strtoupper(trim($key));
@@ -66,6 +69,6 @@ public static function create(int|string $key) : self
                 )
             );
         }
-        return self::$cachedObject[$value] ??= new self($value, $key);
+        return self::$cachedObject[$key] ??= new self($value, $key);
     }
 }
diff --git a/src/ResourceRecord/RRTypes/AAAA.php b/src/ResourceRecord/RRTypes/AAAA.php
index 0aa3ea8..8174c40 100644
--- a/src/ResourceRecord/RRTypes/AAAA.php
+++ b/src/ResourceRecord/RRTypes/AAAA.php
@@ -44,7 +44,7 @@ public function getAddress(): string
      *     class: string,
      *     ttl: int,
      *     type: string,
-     *     ip: string
+     *     ipv6: string
      * }
      */
     public function toArray(): array
diff --git a/src/ResourceRecord/RRTypes/CAA.php b/src/ResourceRecord/RRTypes/CAA.php
index d0f600d..bd47350 100644
--- a/src/ResourceRecord/RRTypes/CAA.php
+++ b/src/ResourceRecord/RRTypes/CAA.php
@@ -4,7 +4,9 @@
 namespace ArrayAccess\DnsRecord\ResourceRecord\RRTypes;
 
 use ArrayAccess\DnsRecord\Abstracts\AbstractResourceRecordType;
+use function is_array;
 use function substr;
+use function unpack;
 
 /**
  * DNS Certification Authority Authorization (CAA) Resource Record - CAA RFC6844
@@ -27,29 +29,32 @@ class CAA extends AbstractResourceRecordType
     /**
      * @var int
      */
-    protected int $flags;
+    protected int $flags = 0;
 
     /**
      * @var string
      */
-    protected string $tag;
+    protected string $tag = '';
 
     /**
      * @var int
      */
-    protected int $tagLength;
+    protected int $tagLength = 0;
 
     /**
      * @inheritdoc
      */
     protected function parseRData(string $message, int $rdataOffset): void
     {
+        $data = unpack('Cflags/CtagLength', substr($this->rData, 0, 2));
+        if (!is_array($data)) {
+            return;
+        }
         // unpack the flags and tag length
         [
             'flags' => $this->flags,
             'tagLength' => $this->tagLength,
-
-        ] = unpack('Cflags/CtagLength', substr($this->rData, 0, 2));
+        ] = $data;
         $this->tag      = substr($this->rData, 2, $this->tagLength);
         $this->value    = substr($this->rData, 2 + $this->tagLength);
     }
@@ -77,7 +82,7 @@ public function getTagLength(): int
      *     type:string,
      *     flags:int,
      *     tag:string,
-     *     value:string,
+     *     value: ?string,
      * }
      */
     public function toArray(): array
@@ -89,7 +94,7 @@ public function toArray(): array
             'type' => $this->getType()->getName(),
             'flags' => $this->getFlags(),
             'tag' => $this->getTag(),
-            'value' => $this->getValue(),
+            'value' => $this->getValue()
         ];
     }
 }
diff --git a/src/ResourceRecord/RRTypes/CERT.php b/src/ResourceRecord/RRTypes/CERT.php
index c7cb8bb..bd9bf84 100644
--- a/src/ResourceRecord/RRTypes/CERT.php
+++ b/src/ResourceRecord/RRTypes/CERT.php
@@ -4,9 +4,10 @@
 namespace ArrayAccess\DnsRecord\ResourceRecord\RRTypes;
 
 use ArrayAccess\DnsRecord\Abstracts\AbstractResourceRecordType;
-use function array_values;
 use function base64_encode;
+use function is_array;
 use function substr;
+use function unpack;
 
 /**
  *
@@ -45,14 +46,18 @@ protected function parseRData(string $message, int $rdataOffset): void
         if ($this->rdLength < 6) {
             return;
         }
+        $data = unpack('nformat/nkeyTag/Calgorithm', $this->rData);
+        if (!is_array($data)) {
+            return;
+        }
         //
         // unpack the format, keytag and algorithm
         //
         [
-            $this->format,
-            $this->keyTag,
-            $this->algorithm
-        ] = array_values(unpack('nformat/nkeytag/Calgorithm', $this->rData));
+            'format' => $this->format,
+            'keyTag' => $this->keyTag,
+            'algorithm' => $this->algorithm
+        ] = $data;
 
         //
         // copy the certificate
diff --git a/src/ResourceRecord/RRTypes/DNSKEY.php b/src/ResourceRecord/RRTypes/DNSKEY.php
index d44683b..4f7df02 100644
--- a/src/ResourceRecord/RRTypes/DNSKEY.php
+++ b/src/ResourceRecord/RRTypes/DNSKEY.php
@@ -5,6 +5,7 @@
 
 use ArrayAccess\DnsRecord\Abstracts\AbstractResourceRecordType;
 use function base64_encode;
+use function is_array;
 use function sprintf;
 use function unpack;
 
@@ -74,13 +75,18 @@ class DNSKEY extends AbstractResourceRecordType
      */
     protected function parseRData(string $message, int $rdataOffset): void
     {
+        $data = unpack("nflags/Cprotocol/Calgorithm/a*pubKey", $this->rData);
+        if (!is_array($data)) {
+            return;
+        }
+
         [
             'flags' => $this->flags,
             // https://datatracker.ietf.org/doc/html/rfc4034#section-2.1.2
             'protocol' => $this->protocol,
             'algorithm' => $this->algorithm,
             'pubKey' => $pubKey,
-        ] = unpack("nflags/Cprotocol/Calgorithm/a*pubKey", $this->rData);
+        ] = $data;
         //  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 = 16
         // convert binary flags
         $flags = sprintf("%016b\n", $this->flags);
diff --git a/src/ResourceRecord/RRTypes/MG.php b/src/ResourceRecord/RRTypes/MG.php
index 1967893..df48af9 100644
--- a/src/ResourceRecord/RRTypes/MG.php
+++ b/src/ResourceRecord/RRTypes/MG.php
@@ -8,7 +8,7 @@
 
 /**
  * MG RDATA format (EXPERIMENTAL) - RFC1035 Section 3.3.6
- * MGMNAME A <domain-name> which specifies a mailbox which is a
+ * MGMNAME A <domain-name> which specifies a mailbox, which is a
  *  member of the mail group specified by the domain name
  *
  *      +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
diff --git a/src/ResourceRecord/RRTypes/MR.php b/src/ResourceRecord/RRTypes/MR.php
index ac22d21..4308f3f 100644
--- a/src/ResourceRecord/RRTypes/MR.php
+++ b/src/ResourceRecord/RRTypes/MR.php
@@ -9,7 +9,7 @@
 /**
  * MR RDATA format (EXPERIMENTAL) - RFC1035 Section 3.3.8
  * NEWNAME A <domain-name> which specifies a mailbox which is the
- * proper rename of the specified mailbox.
+ * proper renamed of the specified mailbox.
  *
  *      +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
  *      /                   NEWNAME                    /
diff --git a/src/ResourceRecord/RRTypes/MX.php b/src/ResourceRecord/RRTypes/MX.php
index 14bdc10..ddfb75a 100644
--- a/src/ResourceRecord/RRTypes/MX.php
+++ b/src/ResourceRecord/RRTypes/MX.php
@@ -5,6 +5,8 @@
 
 use ArrayAccess\DnsRecord\Abstracts\AbstractResourceRecordType;
 use ArrayAccess\DnsRecord\Utils\Buffer;
+use function is_array;
+use function unpack;
 
 /**
  * MX RDATA format - RFC1035 Section 3.3.9
@@ -29,19 +31,23 @@ class MX extends AbstractResourceRecordType
 {
     const TYPE = 'MX';
 
-    protected int $preference;
+    protected int $preference = -1;
 
-    protected string $exchange;
+    protected string $exchange = '';
 
     /**
      * @inheritdoc
      */
     protected function parseRData(string $message, int $rdataOffset): void
     {
-        ['preference' => $this->preference] = unpack(
+        $data = unpack(
             'npreference',
             Buffer::read($message, $rdataOffset, 2)
         );
+        if (!is_array($data)) {
+            return;
+        }
+        ['preference' => $this->preference] = $data;
         $this->exchange = Buffer::readLabel($message, $rdataOffset);
         $this->value = "$this->preference $this->exchange";
     }
diff --git a/src/ResourceRecord/RRTypes/OPT.php b/src/ResourceRecord/RRTypes/OPT.php
index f3aa9e6..903768e 100644
--- a/src/ResourceRecord/RRTypes/OPT.php
+++ b/src/ResourceRecord/RRTypes/OPT.php
@@ -7,6 +7,7 @@
 use ArrayAccess\DnsRecord\Interfaces\ResourceRecord\ResourceRecordMetaTypeInterface;
 use ArrayAccess\DnsRecord\Packet\Message;
 use ArrayAccess\DnsRecord\Utils\Lookup;
+use function is_array;
 use function pack;
 use function unpack;
 
@@ -93,18 +94,24 @@ public static function create(
 
     protected function parseRData(string $message, int $rdataOffset): void
     {
-        [
-            'extended' => $this->extended_rcode,
-            'version' => $this->version,
-            'do' => $do,
-            'z' => $this->z,
-        ] = unpack('Cextended/Cversion/Cdo/Cz', pack('N', $this->ttl));
-        $this->do = ($do >> 7);
-        if ($this->rdLength > 0) {
+        $data = unpack('Cextended/Cversion/Cdo/Cz', pack('N', $this->ttl));
+        if (is_array($data)) {
             [
-                'option_code' => $this->option_code,
-                'option_length' => $this->option_length
-            ] = unpack('noption_code/noption_length', $this->rData);
+                'extended' => $this->extended_rcode,
+                'version' => $this->version,
+                'do' => $do,
+                'z' => $this->z,
+            ] = $data;
+            $this->do = ($do >> 7);
+        }
+        if ($this->rdLength > 0) {
+            $data = unpack('noption_code/noption_length', $this->rData);
+            if (is_array($data)) {
+                [
+                    'option_code' => $this->option_code,
+                    'option_length' => $this->option_length
+                ] = $data;
+            }
             $this->option_data = substr($this->rData, 4);
         }
     }
diff --git a/src/ResourceRecord/RRTypes/RRSIG.php b/src/ResourceRecord/RRTypes/RRSIG.php
index 389f166..c8ed938 100644
--- a/src/ResourceRecord/RRTypes/RRSIG.php
+++ b/src/ResourceRecord/RRTypes/RRSIG.php
@@ -6,6 +6,7 @@
 use ArrayAccess\DnsRecord\Abstracts\AbstractResourceRecordType;
 use ArrayAccess\DnsRecord\Utils\Buffer;
 use function base64_encode;
+use function is_array;
 use function strlen;
 use function unpack;
 
@@ -37,18 +38,21 @@ class RRSIG extends AbstractResourceRecordType
     protected function parseRData(string $message, int $rdataOffset): void
     {
         $stuff = Buffer::read($message, $rdataOffset, 18);
-        [
-            'type' => $this->sigType,
-            'algorithm' => $this->algorithm,
-            'labels' => $this->labels,
-            'originalttl' => $this->originalttl,
-            'expiration' => $this->expiration,
-            'inception' => $this->inception,
-            'keytag' => $this->keyTag,
-        ] = unpack(
+        $stuff = unpack(
             "ntype/calgorithm/clabels/Noriginalttl/Nexpiration/Ninception/nkeytag",
             $stuff
         );
+        if (is_array($stuff)) {
+            [
+                'type' => $this->sigType,
+                'algorithm' => $this->algorithm,
+                'labels' => $this->labels,
+                'originalttl' => $this->originalttl,
+                'expiration' => $this->expiration,
+                'inception' => $this->inception,
+                'keytag' => $this->keyTag,
+            ] = $stuff;
+        }
         $this->signer = Buffer::readLabel($message, $rdataOffset);
         $this->signature = base64_encode(
             Buffer::read($message, $rdataOffset, $this->rdLength - (strlen($this->signer) + 2) - 18)
diff --git a/src/ResourceRecord/RRTypes/SOA.php b/src/ResourceRecord/RRTypes/SOA.php
index f1a9bcc..85f92ad 100644
--- a/src/ResourceRecord/RRTypes/SOA.php
+++ b/src/ResourceRecord/RRTypes/SOA.php
@@ -5,6 +5,7 @@
 
 use ArrayAccess\DnsRecord\Abstracts\AbstractResourceRecordType;
 use ArrayAccess\DnsRecord\Utils\Buffer;
+use function is_array;
 use function sprintf;
 use function unpack;
 
@@ -33,27 +34,30 @@ protected function parseRData($message, int $rdataOffset): void
     {
         $this->mName = Buffer::readLabel($message, $rdataOffset);
         $this->rName = Buffer::readLabel($message, $rdataOffset);
-        [
-            'serial' => $this->serial,
-            'refresh' => $this->refresh,
-            'retry' => $this->retry,
-            'expire' => $this->expire,
-            'minTTL' => $this->minimumTTL
-        ] = unpack(
+        $data = unpack(
             "Nserial/Nrefresh/Nretry/Nexpire/NminTTL",
             Buffer::read($message, $rdataOffset, 20)
         );
-
-        $this->value = sprintf(
-            '%s. %s. %d %d %d %d %d',
-            $this->mName,
-            $this->rName,
-            $this->serial,
-            $this->refresh,
-            $this->retry,
-            $this->expire,
-            $this->minimumTTL
-        );
+        if (is_array($data)) {
+            [
+                'serial' => $this->serial,
+                'refresh' => $this->refresh,
+                'retry' => $this->retry,
+                'expire' => $this->expire,
+                'minTTL' => $this->minimumTTL
+            ] = $data;
+
+            $this->value = sprintf(
+                '%s. %s. %d %d %d %d %d',
+                $this->mName,
+                $this->rName,
+                $this->serial,
+                $this->refresh,
+                $this->retry,
+                $this->expire,
+                $this->minimumTTL
+            );
+        }
     }
 
     public function getMinimumTTL(): int
diff --git a/src/ResourceRecord/RRTypes/SRV.php b/src/ResourceRecord/RRTypes/SRV.php
index 36dfe87..4ad58d7 100644
--- a/src/ResourceRecord/RRTypes/SRV.php
+++ b/src/ResourceRecord/RRTypes/SRV.php
@@ -5,6 +5,7 @@
 
 use ArrayAccess\DnsRecord\Abstracts\AbstractResourceRecordType;
 use ArrayAccess\DnsRecord\Utils\Buffer;
+use function is_array;
 use function unpack;
 
 /**
@@ -27,14 +28,17 @@ class SRV extends AbstractResourceRecordType
     protected function parseRData($message, int $rdataOffset): void
     {
         $offset = 0;
-        [
-            'priority' => $this->priority,
-            'weight' => $this->weight,
-            'port' => $this->port,
-        ] = unpack(
+        $data = unpack(
             'npriority/nweight/nport',
             Buffer::read($this->rData, $offset, 6)
         );
+        if (is_array($data)) {
+            [
+                'priority' => $this->priority,
+                'weight' => $this->weight,
+                'port' => $this->port,
+            ] = $data;
+        }
 
         $this->value = Buffer::readLabel($this->rData, $offset);
     }
@@ -54,6 +58,17 @@ public function getPort(): int
         return $this->port;
     }
 
+    /**
+     * @return array{
+     *     host: string,
+     *     class: string,
+     *     type: string,
+     *     pri: int,
+     *     weight: int,
+     *     port: int,
+     *     target: ?string,
+     * }
+     */
     public function toArray(): array
     {
         return [
diff --git a/src/ResourceRecord/RRTypes/TXT.php b/src/ResourceRecord/RRTypes/TXT.php
index 00e8741..1f82ab7 100644
--- a/src/ResourceRecord/RRTypes/TXT.php
+++ b/src/ResourceRecord/RRTypes/TXT.php
@@ -14,7 +14,7 @@
  *      /                   TXT-DATA                    /
  *      +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
  *
- * @use parent::parseRData() for logic
+ * @see AbstractResourceRecordType::parseRData() for logic
  * @link https://datatracker.ietf.org/doc/html/rfc1035#section-3.3.14
  */
 class TXT extends AbstractResourceRecordType
diff --git a/src/Traits/DisableSetterTrait.php b/src/Traits/DisableSetterTrait.php
index 52bfd2b..358835b 100644
--- a/src/Traits/DisableSetterTrait.php
+++ b/src/Traits/DisableSetterTrait.php
@@ -5,7 +5,7 @@
 
 trait DisableSetterTrait
 {
-    final public function __set(string $name, $value): void
+    final public function __set(string $name, mixed $value): void
     {
         // pass
     }
diff --git a/src/Traits/PacketSenderTrait.php b/src/Traits/PacketSenderTrait.php
index 3616838..989c3a0 100644
--- a/src/Traits/PacketSenderTrait.php
+++ b/src/Traits/PacketSenderTrait.php
@@ -34,6 +34,9 @@
 
 trait PacketSenderTrait
 {
+    /**
+     * @var array<string, resource>
+     */
     private array $sockets = [];
 
     abstract public function getCache(): ?CacheStorageInterface;
@@ -69,6 +72,7 @@ protected function setResourceTimeout($resource, int|float $timeout): void
 
     /**
      * @throws RequestException
+     * @return resource
      */
     final protected function createSocketServer(
         bool $useUDP,
@@ -111,7 +115,7 @@ final protected function createSocketServer(
      * @param bool $useUDP
      * @param string|null $server
      * @param int $port
-     * @param $serverList
+     * @param mixed $serverList
      * @return array{
      *       protocol: string,
      *       server: string,
@@ -125,7 +129,7 @@ final protected function createSocket(
         bool $useUDP,
         ?string $server = null,
         int $port = 53,
-        &$serverList = null
+        mixed &$serverList = null
     ) : array {
         if ($server) {
             $protocol = $useUDP ? "udp" : "tcp";
@@ -151,7 +155,7 @@ final protected function createSocket(
                     sprintf(
                         'Can not connect to server "%s" last error : %s',
                         $server,
-                        ($e->getMessage()??null)?:'Unknown Error'
+                        ($e->getMessage()?:null)?:'Unknown Error'
                     ),
                     $e->getCode()
                 );
@@ -192,13 +196,14 @@ protected function sendCommand(
         set_error_handler(static function ($errCode, $errMsg) use (&$eCode, &$eMessage) {
             $eCode = $errCode;
             $eMessage = $errMsg;
+            return true;
         });
         try {
             $status = fwrite($resource, $query);
             $info = stream_get_meta_data($resource);
             // $isUdp = $info['stream_type'] === 'udp_socket';
             if ($status === false) {
-                $isTimeout = $info && !empty($info['timed_out']);
+                $isTimeout = !empty($info['timed_out']);
                 $eMessage = $eMessage ?: (
                 $isTimeout ? 'Write process timed out' : 'Unknown error while writing data'
                 );
@@ -226,7 +231,7 @@ protected function sendCommand(
             }
 
             if ($data === false) {
-                $isTimeout = $info && !empty($info['timed_out']);
+                $isTimeout = !empty($info['timed_out']);
                 $eMessage = $eMessage ?: (
                 $isTimeout ? 'Read process timed out' : 'Unknown error while reading data'
                 );
@@ -328,8 +333,11 @@ protected function sendTCP(
 
     private function saveResponseCache(PacketResponseInterface $response): void
     {
+        $cache = $this->getCache();
+        if (!$cache) {  // @phpstan-ignore-line
+            return;
+        }
         try {
-            $cache = $this->getCache();
             $cacheTime = null;
             foreach ($response->getAnswers()->getRecords() as $type) {
                 if (!$this->cacheAbleResource($type->getClass()->getName())) {
@@ -353,18 +361,18 @@ private function saveResponseCache(PacketResponseInterface $response): void
     private function getCachePacket(PacketRequestDataInterface $packetRequestData): ?PacketResponseInterface
     {
         $cache = $this->getCache();
-        if (!$cache) {
+        if (!$cache) { // @phpstan-ignore-line
             return null;
         }
         try {
-            if (($response = $this->getCache()->getItem($packetRequestData)) instanceof PacketResponseInterface) {
+            if (($response = $cache->getItem($packetRequestData)) instanceof PacketResponseInterface) {
                 $currentTime = time();
                 $endTime = ($response->getEndTime() / 1000) + CacheStorageInterface::MAXIMUM_TTL;
                 $shouldExpired = $endTime < $currentTime;
                 if (!$shouldExpired) {
                     return $response;
                 }
-                $this->getCache()->deleteItem(
+                $cache->deleteItem(
                     $response->getPacketData()
                 );
             }
@@ -373,12 +381,12 @@ private function getCachePacket(PacketRequestDataInterface $packetRequestData):
         return null;
     }
 
-    /**
+    /*
      * @param string $protocol
      * @param string $server
      * @param string $port
      * @return void
-     */
+     * unused
     private function closeSocket(
         string $protocol,
         string $server,
@@ -391,8 +399,12 @@ private function closeSocket(
             fclose($this->sockets["$protocol://$server:$port"]);
         }
         unset($this->sockets["$protocol://$server:$port"]);
-    }
+    }*/
 
+    /**
+     * @param resource $resource
+     * @return bool
+     */
     private function closeSocketResource(&$resource): bool
     {
         if (!is_resource($resource)) {
@@ -400,12 +412,11 @@ private function closeSocketResource(&$resource): bool
         }
         try {
             $meta = stream_get_meta_data($resource);
-            $uri = $meta['uri'] ?? null;
+            $uri = !empty($meta['uri']) ? $meta['uri'] : null;
+            fclose($resource);
             if (!$uri) {
-                fclose($resource);
                 return true;
             }
-            fclose($resource);
             if (isset($this->sockets[$uri])) {
                 unset($this->sockets[$uri]);
             }
diff --git a/src/Utils/Addresses.php b/src/Utils/Addresses.php
index 63efccb..84f0e51 100644
--- a/src/Utils/Addresses.php
+++ b/src/Utils/Addresses.php
@@ -187,6 +187,9 @@ public static function filterDomain(mixed $domainName): ?string
 
         if ($intl_idn) {
             $domainName = $isAscii ? idn_to_utf8($domainName) : idn_to_ascii($domainName);
+            if (!$domainName) {
+                return null;
+            }
             // revert
             $domainName = ($isAscii ? idn_to_ascii($domainName) : idn_to_utf8($domainName)) ?: null;
             if (!$domainName) {
@@ -196,8 +199,12 @@ public static function filterDomain(mixed $domainName): ?string
         } else {
             foreach ($labels as &$label) {
                 if (preg_match('/[^x00-x7F]/', $domainName)) {
-                    $label = 'xn--' . self::punycodeEncode($label);
-                    if (!$label || strlen($label) > 63) {
+                    $encode = self::punycodeEncode($label);
+                    if (!$encode) {
+                        return null;
+                    }
+                    $label = 'xn--' . $encode;
+                    if (strlen($label) > 63) {
                         return null;
                     }
                 }
@@ -365,14 +372,11 @@ private static function utf8Decode(string $input): array
 
         for ($i = 0; $i < $length; ++$i) {
             $byte = ord($input[$i]);
-
             if (0 === $bytesNeeded) {
-                if ($byte >= 0x00 && $byte <= 0x7F) {
+                if ($byte >= 0x00 && $byte <= 0x7F) { // @phpstan-ignore-line
                     $codePoints[] = $byte;
-
                     continue;
                 }
-
                 if ($byte >= 0xC2 && $byte <= 0xDF) {
                     $bytesNeeded = 1;
                     $codePoint = $byte & 0x1F;
diff --git a/src/Utils/Buffer.php b/src/Utils/Buffer.php
index 01d3830..433a68c 100644
--- a/src/Utils/Buffer.php
+++ b/src/Utils/Buffer.php
@@ -5,11 +5,11 @@
 namespace ArrayAccess\DnsRecord\Utils;
 
 use ArrayAccess\DnsRecord\Exceptions\EmptyArgumentException;
+use ArrayAccess\DnsRecord\Interfaces\Packet\PacketHeaderInterface;
 use ArrayAccess\DnsRecord\Interfaces\Packet\PacketQuestionInterface;
 use ArrayAccess\DnsRecord\Interfaces\ResourceRecord\ResourceRecordClassInterface;
 use ArrayAccess\DnsRecord\Interfaces\ResourceRecord\ResourceRecordQTypeDefinitionInterface;
 use ArrayAccess\DnsRecord\Interfaces\ResourceRecord\ResourceRecordTypeInterface;
-use ArrayAccess\DnsRecord\Packet\Header;
 use ArrayAccess\DnsRecord\ResourceRecord\RRTypes\OPT;
 use function chr;
 use function explode;
@@ -88,11 +88,11 @@ public static function readLabel(string $buffer, int &$offset, string $delimiter
      *
      * @see Header
      * @link https://datatracker.ietf.org/doc/html/rfc5395#section-2
-     * @param Header $header
+     * @param PacketHeaderInterface $header
      *
      * @return string
      */
-    public static function createHeaderMessage(Header $header) : string
+    public static function createHeaderMessage(PacketHeaderInterface $header) : string
     {
         $message  = pack('n', $header->getId());
         $message .= chr(
@@ -130,7 +130,7 @@ public static function createHeaderMessage(Header $header) : string
     public static function createQuestionMessage(PacketQuestionInterface $rr): string
     {
         $message  = self::compressLabel($rr->getName());
-        $message .= self::compressHeader($rr->getType(), $rr->getClass());
+        $message .= self::compressHeader($rr->getType()??'', $rr->getClass()??'');
         return $message;
     }
 
@@ -174,7 +174,7 @@ public static function compressLabel(string $name): string
             );
         }
 
-        $name = preg_replace('~\\\+.~', '.', $name);
+        $name = (string) preg_replace('~\\\+.~', '.', $name);
         $computedName = '';
         foreach (explode('.', $name) as $label) {
             if ($label === '') {
diff --git a/src/Utils/Caller.php b/src/Utils/Caller.php
index 2665fb7..be82c4f 100644
--- a/src/Utils/Caller.php
+++ b/src/Utils/Caller.php
@@ -14,13 +14,14 @@ class Caller
      */
     public static function track(
         callable $callable,
-        &$errorCode = 0,
-        &$errorMessage = '',
-        &...$args
-    ) {
+        mixed &$errorCode = 0,
+        mixed &$errorMessage = '',
+        mixed &...$args
+    ) : mixed {
         set_error_handler(static function ($code, $message) use (&$errorCode, &$errorMessage) {
             $errorCode = $code;
             $errorMessage = $message;
+            return true;
         });
         try {
             return $callable(...$args);
@@ -39,9 +40,9 @@ public static function track(
      */
     public static function call(
         callable $callable,
-        ...$args
-    ) {
-        set_error_handler(static fn () => null);
+        mixed ...$args
+    ) : mixed {
+        set_error_handler(static fn () => true);
         try {
             return $callable(...$args);
         } finally {
diff --git a/src/Utils/Lookup.php b/src/Utils/Lookup.php
index cc43148..5f968bf 100644
--- a/src/Utils/Lookup.php
+++ b/src/Utils/Lookup.php
@@ -90,6 +90,9 @@ class Lookup
         'DSO'    => self::OPCODE_DSO,
     ];
 
+    /**
+     * @var class-string<ResourceRecordOpcodeInterface>[]|ResourceRecordOpcodeInterface[]
+     */
     private static array $opcodeCache = [
         self::OPCODE_QUERY  => Query::class,
         self::OPCODE_IQUERY => IQuery::class,
diff --git a/tests/Cache/CacheStorageTest.php b/tests/Cache/CacheStorageTest.php
index 93ff3c1..10f8244 100644
--- a/tests/Cache/CacheStorageTest.php
+++ b/tests/Cache/CacheStorageTest.php
@@ -41,8 +41,9 @@ private function createFakePacketRequestData() : PacketRequestDataInterface
     {
         return new class implements PacketRequestDataInterface
         {
-            public function serialize()
+            public function serialize() : ?string
             {
+                return null;
             }
 
             public function unserialize(string $data)
@@ -100,11 +101,18 @@ public function createRequest(?CacheStorageInterface $cacheStorage = null): Pack
                 return (new ReflectionClass(Request::class))->newInstanceWithoutConstructor();
             }
 
+            /**
+             * @return array{}
+             */
             public function __serialize(): array
             {
                 return [];
             }
 
+            /**
+             * @param array{} $data
+             * @return void
+             */
             public function __unserialize(array $data): void
             {
             }
@@ -124,7 +132,7 @@ private function createFakeResponse(): Response
         );
     }
 
-    public function testGetCacheName()
+    public function testGetCacheName() : void
     {
         $cacheName = $this->cacheStorage->getCacheName(
             $this->createFakePacketRequestData()
@@ -151,7 +159,7 @@ public function testGetCacheName()
         );
     }
 
-    public function testGetAdapter()
+    public function testGetAdapter() : void
     {
         /**
          * @see self::testSetAdapter()
@@ -165,7 +173,7 @@ public function testGetAdapter()
         );
     }
 
-    public function testSetAdapter()
+    public function testSetAdapter() : void
     {
         $cacheAdapter = new ArrayCacheAdapter();
         /**
@@ -173,7 +181,7 @@ public function testSetAdapter()
          * @noinspection PhpVoidFunctionResultUsedInspection
          */
         $this->assertNull(
-            $this->cacheStorage->setAdapter($cacheAdapter),
+            $this->cacheStorage->setAdapter($cacheAdapter), // @phpstan-ignore-line
             sprintf(
                 '%1$s->setAdapter(%2$s) should no return',
                 $this->cacheStorageClassName,
@@ -192,7 +200,7 @@ public function testSetAdapter()
         );
     }
 
-    public function testSaveItem()
+    public function testSaveItem() : void
     {
         $fakeResponse = $this->createFakeResponse();
         $this->assertFalse(
@@ -215,7 +223,7 @@ public function testSaveItem()
         );
     }
 
-    public function testGetItem()
+    public function testGetItem() : void
     {
         $key = 'nothing';
         $this->assertNull(
@@ -261,7 +269,7 @@ public function testGetItem()
         );
     }
 
-    public function testDeleteItem()
+    public function testDeleteItem() : void
     {
         $key = 'nothing';
         $this->assertFalse(
@@ -287,7 +295,7 @@ public function testDeleteItem()
         );
     }
 
-    public function testDeleteItems()
+    public function testDeleteItems() : void
     {
         $key = 'nothing';
         $this->assertFalse(
@@ -313,7 +321,7 @@ public function testDeleteItems()
         );
     }
 
-    public function testHasItem()
+    public function testHasItem() : void
     {
         $fakeResponse = $this->createFakeResponse();
         $this->assertFalse(
diff --git a/tests/DnsServer/CustomDnsServerTest.php b/tests/DnsServer/CustomDnsServerTest.php
index dd427f1..f298efd 100644
--- a/tests/DnsServer/CustomDnsServerTest.php
+++ b/tests/DnsServer/CustomDnsServerTest.php
@@ -7,11 +7,11 @@
 use ArrayAccess\DnsRecord\Interfaces\DnsServer\DnsServerInterface;
 use PHPUnit\Framework\TestCase;
 use function sprintf;
+use function unserialize;
 
 class CustomDnsServerTest extends TestCase
 {
-
-    public function testConstruct()
+    public function testConstruct() : void
     {
         $this->assertInstanceOf(
             DnsServerInterface::class,
@@ -24,7 +24,7 @@ public function testConstruct()
         );
     }
 
-    public function testCreate()
+    public function testCreate() : void
     {
         $dns = '8.8.8.8';
         $customDns = CustomDnsServer::create($dns);
@@ -65,4 +65,45 @@ public function testCreate()
             )
         );
     }
+
+    public function testSerializeUnserialize() : void
+    {
+        $customDns = CustomDnsServer::create('8.8.8.8', '8.8.4.4');
+        $this->assertInstanceOf(
+            CustomDnsServer::class,
+            unserialize(serialize($customDns)),
+            sprintf(
+                'unserialize(serialize(%1$s)) should restore object',
+                CustomDnsServer::class
+            )
+        );
+
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $this->assertIsString(
+            $customDns->serialize(),
+            sprintf(
+                '%1$s->serialize() should serialized string',
+                CustomDnsServer::class
+            )
+        );
+
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $this->assertSame(
+            [
+                'identity' => $customDns->getIdentity(),
+                'name' => $customDns->getName(),
+                'primaryServer' => $customDns->getPrimaryServer(),
+                'secondaryServer' => $customDns->getSecondaryServer(),
+                'port' => $customDns->getPort()
+            ],
+            unserialize($customDns->serialize()),
+            'Checking unserialize value for consistency'
+        );
+        /** @noinspection PhpUnhandledExceptionInspection */
+        /** @noinspection PhpVoidFunctionResultUsedInspection */
+        $this->assertNull(
+            $customDns->unserialize($customDns->serialize()), // @phpstan-ignore-line
+            '%1$s->unserialize(%1$s->serialize()) should no return'
+        );
+    }
 }
diff --git a/tests/DnsServerStorageTest.php b/tests/DnsServerStorageTest.php
index e56aadc..bb41ce2 100644
--- a/tests/DnsServerStorageTest.php
+++ b/tests/DnsServerStorageTest.php
@@ -23,6 +23,9 @@ class DnsServerStorageTest extends TestCase
 {
     protected DnsServerStorage $dnsServerStorage;
 
+    /**
+     * @var class-string<DnsServerStorage>
+     */
     protected string $dnsClassName;
 
     /**
@@ -36,7 +39,7 @@ public function setUp(): void
         $this->dnsClassName = $this->dnsServerStorage::class;
     }
 
-    public function testObject()
+    public function testObject() : void
     {
         $google = new Google();
         $this->assertContains(
@@ -77,7 +80,7 @@ public function testObject()
         );
     }
 
-    public function testGetServers()
+    public function testGetServers() : void
     {
         $this->assertNotEmpty(
             $this->dnsServerStorage->getServers(),
@@ -88,7 +91,7 @@ public function testGetServers()
         );
     }
 
-    public function testCount()
+    public function testCount() : void
     {
         $this->assertCount(
             count($this->dnsServerStorage->getServers()),
@@ -100,7 +103,7 @@ public function testCount()
         );
     }
 
-    public function testGetIterator()
+    public function testGetIterator() : void
     {
         $this->assertInstanceOf(
             ArrayIterator::class,
@@ -132,7 +135,7 @@ public function testGetIterator()
         }
     }
 
-    public function testRemove()
+    public function testRemove() : void
     {
         $servers = $this->dnsServerStorage->getServers();
         $total = count($servers);
@@ -141,7 +144,7 @@ public function testRemove()
          * @noinspection PhpVoidFunctionResultUsedInspection
          */
         $this->assertNull(
-            $this->dnsServerStorage->remove(reset($servers)),
+            $this->dnsServerStorage->remove(reset($servers)), // @phpstan-ignore-line
             sprintf(
                 '%s->remove() should no return',
                 $this->dnsClassName
@@ -155,14 +158,25 @@ public function testRemove()
                 $this->dnsClassName
             )
         );
+        $this->assertSame(
+            count($this->dnsServerStorage),
+            $this->dnsServerStorage->count(),
+            sprintf(
+                'count(%1$s) should identical with %1$s->count()',
+                $this->dnsClassName
+            )
+        );
     }
 
-    public function testGet()
+    public function testGet() : void
     {
         $this->assertNull(
             $this->dnsServerStorage->get('not_exist_server'),
             'Dns server identity "not_exist_server" should not exist'
         );
+        /**
+         * @var Google $google
+         */
         $google = $this->dnsServerStorage::getDefaultServer(Google::class);
         $this->assertSame(
             $this->dnsServerStorage->get($google->getIdentity()),
@@ -185,7 +199,7 @@ public function testGet()
             )
         );
         $this->assertSame(
-            $this->dnsServerStorage->get($google)->getIdentity(),
+            $this->dnsServerStorage->get($google)?->getIdentity(),
             $google::class,
             sprintf(
                 'Method %1$s->get(%2$s)->getIdentity() should equal with id %3$s',
@@ -196,7 +210,7 @@ public function testGet()
         );
     }
 
-    public function testAdd()
+    public function testAdd() : void
     {
         $total = count($this->dnsServerStorage);
 
@@ -206,7 +220,7 @@ public function testAdd()
          * @noinspection PhpVoidFunctionResultUsedInspection
          */
         $this->assertNull(
-            $this->dnsServerStorage->add($custom),
+            $this->dnsServerStorage->add($custom), // @phpstan-ignore-line
             sprintf(
                 '%1$s->add(%2$s) should no return',
                 $this->dnsClassName,
@@ -258,7 +272,7 @@ public function testAdd()
         );
     }
 
-    public function testGetDefaultServer()
+    public function testGetDefaultServer() : void
     {
         $this->assertInstanceOf(
             Google::class,
@@ -281,7 +295,7 @@ public function testGetDefaultServer()
         );
     }
 
-    public function testCreateDefault()
+    public function testCreateDefault() : void
     {
         $this->assertInstanceOf(
             $this->dnsClassName,
@@ -313,7 +327,7 @@ public function testCreateDefault()
         );
     }
 
-    public function testSerialize()
+    public function testSerialize() : void
     {
         try {
             // just reduce error
@@ -346,9 +360,26 @@ public function testSerialize()
                 $this->dnsClassName
             )
         );
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $this->assertIsString(
+            $this->dnsServerStorage->serialize(),
+            sprintf(
+                '%1$s->serialize() should string',
+                $this->dnsClassName
+            )
+        );
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $this->assertArrayHasKey(
+            'servers',
+            unserialize($this->dnsServerStorage->serialize()),
+            sprintf(
+                'unserialize(%1$s->serialize()) should array has key "servers"',
+                $this->dnsClassName
+            )
+        );
     }
 
-    public function testUnserialize()
+    public function testUnserialize() : void
     {
         try {
             $object = unserialize(serialize($this->dnsServerStorage));
@@ -363,5 +394,16 @@ public function testUnserialize()
                 $this->dnsClassName
             )
         );
+        /** @noinspection PhpVoidFunctionResultUsedInspection */
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $this->assertNull(
+            $this->dnsServerStorage->unserialize(  // @phpstan-ignore-line
+                $this->dnsServerStorage->serialize()
+            ),
+            sprintf(
+                '%1$s->unserialize(%1$s->serialize()) should no return',
+                $this->dnsClassName
+            )
+        );
     }
 }
diff --git a/tests/Packet/HeaderTest.php b/tests/Packet/HeaderTest.php
index dd41309..0040f06 100644
--- a/tests/Packet/HeaderTest.php
+++ b/tests/Packet/HeaderTest.php
@@ -16,7 +16,7 @@ class HeaderTest extends TestCase
      *
      * @see \Tests\ArrayAccess\DnsRecord\Utils\BufferTest::testCreateQuestionMessage()
      */
-    public function testFromMessage()
+    public function testFromMessage() : void
     {
         try {
             Header::fromMessage('');
diff --git a/tests/Packet/MessageTest.php b/tests/Packet/MessageTest.php
index dc17a7f..dd985c6 100644
--- a/tests/Packet/MessageTest.php
+++ b/tests/Packet/MessageTest.php
@@ -11,7 +11,7 @@
 
 class MessageTest extends TestCase
 {
-    public function testToString()
+    public function testToString() : void
     {
         $message = md5(microtime());
         $this->assertSame(
@@ -25,7 +25,7 @@ public function testToString()
         );
     }
 
-    public function testGetMessage()
+    public function testGetMessage() : void
     {
         $message = md5(microtime());
         $this->assertSame(
diff --git a/tests/ResolverTest.php b/tests/ResolverTest.php
index ee8b628..bff9569 100644
--- a/tests/ResolverTest.php
+++ b/tests/ResolverTest.php
@@ -28,7 +28,7 @@
  */
 class ResolverTest extends TestCase
 {
-    public function testSetDnsServerStorage()
+    public function testSetDnsServerStorage() : void
     {
         $resolver = new Resolver();
         $dnsServerStorage = $resolver->getDnsServerStorage();
@@ -43,7 +43,7 @@ public function testSetDnsServerStorage()
         );
     }
 
-    public function testGetDnsServerStorage()
+    public function testGetDnsServerStorage() : void
     {
         $resolver = new Resolver();
         $dnsServerStorage = $resolver->getDnsServerStorage();
@@ -67,7 +67,7 @@ public function testGetDnsServerStorage()
         );
     }
 
-    public function testSetCache()
+    public function testSetCache() : void
     {
         $resolver = new Resolver();
         $cache = $resolver->getCache();
@@ -82,7 +82,7 @@ public function testSetCache()
         );
     }
 
-    public function testGetCache()
+    public function testGetCache() : void
     {
         $resolver = new Resolver();
         $cache = $resolver->getCache();
@@ -123,7 +123,7 @@ public function testGetCache()
         );
     }
 
-    public function testQuery()
+    public function testQuery() : void
     {
         $resolver = new Resolver();
         $query = $resolver->query('example.com');
@@ -160,7 +160,7 @@ public function testQuery()
         );
     }
 
-    public function testIQuery()
+    public function testIQuery() : void
     {
         $resolver = new Resolver();
         $query = $resolver->iQuery('example.com');
@@ -184,7 +184,7 @@ public function testIQuery()
         );
     }
 
-    public function testLookup()
+    public function testLookup() : void
     {
         $resolver = new Resolver(
             DnsServerStorage::createDefault(),
@@ -223,7 +223,7 @@ public function testLookup()
         );
     }
 
-    public function testLookups()
+    public function testLookups() : void
     {
         $resolver = new Resolver();
         $lookups = $resolver->lookups(
@@ -268,12 +268,12 @@ public function testLookups()
             );
             $this->assertSame(
                 'example.com',
-                $lookups['A']->getAnswers()->getQuestion()->getName(),
+                $lookups['A']->getAnswers()->getQuestion()?->getName(),
                 'Question name lookup should example.com'
             );
             $this->assertSame(
                 IN::NAME,
-                $lookups['A']->getAnswers()->getQuestion()->getClass()->getName(),
+                $lookups['A']->getAnswers()->getQuestion()->getClass()?->getName(),
                 sprintf(
                     'Question class name lookup should %s',
                     IN::NAME
@@ -326,12 +326,12 @@ public function testLookups()
             );
             $this->assertSame(
                 'example.com',
-                $lookups['B']->getAnswers()->getQuestion()->getName(),
+                $lookups['B']->getAnswers()->getQuestion()?->getName(),
                 'Question name lookup should example.com'
             );
             $this->assertSame(
                 IN::NAME,
-                $lookups['B']->getAnswers()->getQuestion()->getClass()->getName(),
+                $lookups['B']->getAnswers()->getQuestion()->getClass()?->getName(),
                 sprintf(
                     'Question class name lookup should %s',
                     IN::NAME
@@ -349,4 +349,45 @@ public function testLookups()
             );
         }
     }
+
+    public function testSetGetFlag() : void
+    {
+        $resolver = new Resolver();
+        $this->assertFalse(
+            $resolver->isCdFlag(),
+            'CDFlag default set to false'
+        );
+        $this->assertTrue(
+            $resolver->isAdFlag(),
+            'ADFlag default set to true'
+        );
+        $this->assertFalse(
+            $resolver->isDnsSec(),
+            'DNSSec default set to false'
+        );
+        $this->assertTrue(
+            $resolver->isRecurse(),
+            'Recurse default set to true'
+        );
+        $resolver->setCdFlag(true);
+        $this->assertTrue(
+            $resolver->isCdFlag(),
+            'CDFlag after set true'
+        );
+        $resolver->setAdFlag(false);
+        $this->assertFalse(
+            $resolver->isAdFlag(),
+            'CDFlag after set false'
+        );
+        $resolver->setDnsSec(true);
+        $this->assertTrue(
+            $resolver->isDnsSec(),
+            'DNSSec set false'
+        );
+        $resolver->setRecurse(false);
+        $this->assertFalse(
+            $resolver->isRecurse(),
+            'Recurse set false'
+        );
+    }
 }
diff --git a/tests/Utils/AddressesTest.php b/tests/Utils/AddressesTest.php
index b0c9f32..5d88202 100644
--- a/tests/Utils/AddressesTest.php
+++ b/tests/Utils/AddressesTest.php
@@ -13,7 +13,7 @@
 class AddressesTest extends TestCase
 {
 
-    public function testFilterDomain()
+    public function testFilterDomain() : void
     {
         $baseDomain = 'example.com'; // base domain
         $httpsDomainWithPort = "https://$baseDomain:443/";
@@ -99,7 +99,7 @@ public function testFilterDomain()
         );
     }
 
-    public function testFilterIp()
+    public function testFilterIp() : void
     {
         $invalidIP = '127.0.0.';
         $validLocalIP = '127.0.0.1';
@@ -156,7 +156,7 @@ public function testFilterIp()
         );
     }
 
-    public function testFilterIpv4()
+    public function testFilterIpv4() : void
     {
         $invalidIP = '::1';
         $validLocalIP = '127.0.0.1';
@@ -177,7 +177,7 @@ public function testFilterIpv4()
         );
     }
 
-    public function testFilterIpv6()
+    public function testFilterIpv6() : void
     {
         $invalidIP = '127.0.0.1';
         $validLocalIP = '::1';
@@ -198,7 +198,7 @@ public function testFilterIpv6()
         );
     }
 
-    public function testReverseIp()
+    public function testReverseIp() : void
     {
         $invalidIP = '127.0.0.';
         $invalidIPv6 = '::1:::';
@@ -246,7 +246,7 @@ public function testReverseIp()
         );
     }
 
-    public function testGuessDNSServer()
+    public function testGuessDNSServer() : void
     {
         $invalidIP = '127.0.0.';
         $validIP = '127.0.0.1';
diff --git a/tests/Utils/BufferTest.php b/tests/Utils/BufferTest.php
index bad770b..504fc09 100644
--- a/tests/Utils/BufferTest.php
+++ b/tests/Utils/BufferTest.php
@@ -14,7 +14,7 @@
 class BufferTest extends TestCase
 {
 
-    public function testRead()
+    public function testRead() : void
     {
         $printed = 'printed';
         $skipped = '_skipped';
@@ -66,7 +66,7 @@ public function testRead()
         );
     }
 
-    public function testCreateHeaderMessage()
+    public function testCreateHeaderMessage() : void
     {
         $header = Header::createQueryHeader();
         $this->assertSame(
@@ -79,7 +79,7 @@ public function testCreateHeaderMessage()
         );
     }
 
-    public function testCompressLabel()
+    public function testCompressLabel() : void
     {
         $domain = 'example.com';
         $label = Buffer::compressLabel($domain);
@@ -94,7 +94,7 @@ public function testCompressLabel()
         );
     }
 
-    public function testReadLabel()
+    public function testReadLabel() : void
     {
         $offset = 0;
         $domain = 'example.com';
@@ -171,7 +171,7 @@ public function testReadLabel()
         );
     }
 
-    public function testCompressHeader()
+    public function testCompressHeader() : void
     {
         $header = Buffer::compressHeader(
             'A',
@@ -187,16 +187,19 @@ public function testCompressHeader()
         );
     }
 
-    public function testCreateQuestionMessage()
+    public function testCreateQuestionMessage() : void
     {
         $question = Question::fromFilteredResponse(
             'example.com',
             Lookup::RR_TYPES['A'],
             Lookup::QCLASS_IN
         );
+        /**
+         * @var non-empty-string $header
+         */
         $header = Buffer::compressHeader(
-            $question->getType(),
-            $question->getClass()
+            $question->getType(), // @phpstan-ignore-line
+            $question->getClass() // @phpstan-ignore-line
         );
         $message = Buffer::createQuestionMessage($question);
         // header is on the end of binary string
diff --git a/tests/Utils/CallerTest.php b/tests/Utils/CallerTest.php
index 9442763..489cbdd 100644
--- a/tests/Utils/CallerTest.php
+++ b/tests/Utils/CallerTest.php
@@ -18,7 +18,7 @@ class CallerTest extends TestCase
 {
 
     #[WithoutErrorHandler]
-    public function testCall()
+    public function testCall() : void
     {
         $message = 'sample: '.md5(microtime());
         $code = rand(0, 10);
@@ -56,7 +56,7 @@ public function testCall()
     }
 
     #[WithoutErrorHandler]
-    public function testTrack()
+    public function testTrack() : void
     {
         $message = 'Message 1';
         @trigger_error($message, E_USER_WARNING);
diff --git a/tests/Utils/LookupTest.php b/tests/Utils/LookupTest.php
index 7e49d2a..b5b5084 100644
--- a/tests/Utils/LookupTest.php
+++ b/tests/Utils/LookupTest.php
@@ -28,7 +28,7 @@
 class LookupTest extends TestCase
 {
 
-    public function testResourceClass()
+    public function testResourceClass() : void
     {
         $exception = null;
         try {
@@ -81,7 +81,7 @@ public function testResourceClass()
         );
     }
 
-    public function testResourceOpcode()
+    public function testResourceOpcode() : void
     {
         $exception = null;
         try {
@@ -177,7 +177,7 @@ public function testResourceOpcode()
         );
     }
 
-    public function testResourceType()
+    public function testResourceType() : void
     {
         $exception = null;
         try {
@@ -230,7 +230,7 @@ public function testResourceType()
         );
     }
 
-    public function testSocket()
+    public function testSocket() : void
     {
         /*
          * protocol:string, server:string, port:int, socket: resource