*=> Add rules to firewall programmatically (using Firewall API):

ScreenTask/FirewallConf.cs

@@ -0,0 +1,44 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using NetFwTypeLib;
+
+namespace ScreenTask
+{
+    class FirewallConf
+    {
+        public void AddRule(String name, String Description,
+           NET_FW_ACTION_ Action, NET_FW_RULE_DIRECTION_ Direction, String LocalPort,
+           bool Enabled = true, int Protocole = 6, String RemoteAdresses = "localsubnet", String ApplicationName = "ScreenTask")
+        {
+            Type Policy2 = Type.GetTypeFromProgID("HNetCfg.FwPolicy2", false);
+            INetFwPolicy2 FwPolicy = (INetFwPolicy2)Activator.CreateInstance(Policy2);
+            INetFwRules rules = FwPolicy.Rules;
+            //Delete if exist to avoid deplicated rules
+            DeleteRule(name);
+            Type RuleType = Type.GetTypeFromProgID("HNetCfg.FWRule");
+            INetFwRule rule = (INetFwRule)Activator.CreateInstance(RuleType);
+
+            rule.Name = name;
+            rule.Description = Description;
+            rule.Protocol = Protocole;// TCP/IP
+            rule.LocalPorts = LocalPort;
+            rule.RemoteAddresses = RemoteAdresses;
+            rule.Action = Action;
+            rule.Direction = Direction;
+            rule.ApplicationName = ApplicationName;
+            rule.Enabled = true;
+            //Add Rule
+            rules.Add(rule);
+        }
+        public void DeleteRule(String RuleName)
+        {
+            Type Policy2 = Type.GetTypeFromProgID("HNetCfg.FwPolicy2", false);
+            INetFwPolicy2 FwPolicy = (INetFwPolicy2)Activator.CreateInstance(Policy2);
+            INetFwRules rules = FwPolicy.Rules;
+
+            rules.Remove(RuleName);
+        }
+    }
+}

ScreenTask/ScreenTask.csproj

@@ -53,6 +53,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="FirewallConf.cs" />
     <Compile Include="frmMain.cs">
       <SubType>Form</SubType>
     </Compile>
@@ -102,6 +103,17 @@
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
   </ItemGroup>
+  <ItemGroup>
+    <COMReference Include="NetFwTypeLib">
+      <Guid>{58FBCF7C-E7A9-467C-80B3-FC65E8FCCA08}</Guid>
+      <VersionMajor>1</VersionMajor>
+      <VersionMinor>0</VersionMinor>
+      <Lcid>0</Lcid>
+      <WrapperTool>tlbimp</WrapperTool>
+      <Isolated>False</Isolated>
+      <EmbedInteropTypes>True</EmbedInteropTypes>
+    </COMReference>
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.

ScreenTask/ScreenTask.sln

@@ -0,0 +1,20 @@
+
+Microsoft Visual Studio Solution File, Format Version 11.00
+# Visual Studio 2010
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ScreenTask", "ScreenTask.csproj", "{4C0A04E9-E7C5-4F57-AA86-2551D5136566}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{4C0A04E9-E7C5-4F57-AA86-2551D5136566}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{4C0A04E9-E7C5-4F57-AA86-2551D5136566}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{4C0A04E9-E7C5-4F57-AA86-2551D5136566}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{4C0A04E9-E7C5-4F57-AA86-2551D5136566}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+EndGlobal

ScreenTask/frmMain.cs

@@ -14,6 +14,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using System.Windows.Forms;
+using NetFwTypeLib;
 
 namespace ScreenTask
 {
@@ -286,44 +287,21 @@ private Task AddFirewallRule(int port)
         {
             return Task.Run(() =>
             {
-
-                string cmd = RunCMD("netsh advfirewall firewall show rule \"Screen Task\"");
-                if (cmd.StartsWith("\r\nNo rules match the specified criteria."))
-                {
-                    cmd = RunCMD("netsh advfirewall firewall add rule name=\"Screen Task\" dir=in action=allow remoteip=localsubnet protocol=tcp localport=" + port);
-                    if (cmd.Contains("Ok."))
-                    {
-                        Log("Screen Task Rule added to your firewall");
-                    }
-                }
-                else
-                {
-                    cmd = RunCMD("netsh advfirewall firewall delete rule name=\"Screen Task\"");
-                    cmd = RunCMD("netsh advfirewall firewall add rule name=\"Screen Task\" dir=in action=allow remoteip=localsubnet protocol=tcp localport=" + port);
-                    if (cmd.Contains("Ok."))
-                    {
-                        Log("Screen Task Rule updated to your firewall");
-                    }
+                FirewallConf cnf = new FirewallConf();
+
+                try 
+	            {	        
+		            cnf.AddRule("Screen Task", "Allow incoming network traffic", NET_FW_ACTION_.NET_FW_ACTION_ALLOW,
+                    NET_FW_RULE_DIRECTION_.NET_FW_RULE_DIR_IN, port+"");
+                    Log("Screen Task Rule added to your firewall");
                 }
+	                catch (Exception ex)
+	                {
+		                Log(ex.Message);
+	                }
             });
 
         }
-        private string RunCMD(string cmd)
-        {
-            Process proc = new Process();
-            proc.StartInfo.FileName = "cmd.exe";
-            proc.StartInfo.Arguments = "/C " + cmd;
-            proc.StartInfo.CreateNoWindow = true;
-            proc.StartInfo.UseShellExecute = false;
-            proc.StartInfo.RedirectStandardOutput = true;
-            proc.StartInfo.RedirectStandardError = true;
-            proc.Start();
-            string res = proc.StandardOutput.ReadToEnd();
-            proc.StandardOutput.Close();
-
-            proc.Close();
-            return res;
-        }
         private void Log(string text)
         {
             txtLog.Text += DateTime.Now.ToShortDateString() + " " + DateTime.Now.ToShortTimeString() + " : " + text + "\r\n";