Expand a bit on the remote access instructions

advocacy_docs/supported-open-source/barman/single-server-streaming/step01-db-setup.mdx

@@ -102,20 +102,42 @@ host all all all md5
 host   replication    streaming_barman   all md5
 ```
 
-### enable remote access to your PostgreSQL Server
+### Enable remote access to your PostgreSQL Server
 
-set `listen_addresses = '*'` in `postgresql.conf`
+If the PostgreSQL server isn't already configured for remote access, or is restricted to connections from known machines, our database server won't be able to connect.
 
-otherwise the barman-backup server will not be able to communicate with your PostgreSQL server at all.
+We'll use psql to check this setting:
 
-### Database settings for streaming
+```shell
+psql -d pagila
+```
 
-We'll also need to make sure there are replication slots available, and that PostgreSQL will allow another sender to connect. We'll use psql to check the current settings:
+The relevant configuration parameter is [`listen_addresses`](https://www.postgresql.org/docs/current/runtime-config-connection.html#GUC-LISTEN-ADDRESSES):
 
 ```shell
-psql -d pagila
+show listen_addresses;
+__OUTPUT__
+ listen_addresses 
+------------------
+ *
+(1 row)
 ```
 
+The value for this server is `*` - which allows connections from anything. This doesn't need to be changed. If the value were to be empty, `localhost`, or a list of hosts or addresses that don't include our database server, we'd need to add its hostname (`backup`) to the list, or change it to the wildcard. 
+
+```shell
+pagila=# ALTER SYSTEM SET listen_addresses TO "*";
+__OUTPUT__
+ALTER SYSTEM
+```
+
+!!! Note
+    If you change this setting, you'll need to restart the database server for it to take effect. Since our setting was already allowing all remote connections, we don't need to do that.
+
+### Database settings for streaming
+
+We'll also need to make sure there are replication slots available, and that PostgreSQL will allow another sender to connect. We'll continue to use psql to check the current settings:
+
 ```sql
 Show max_wal_senders;
 Show max_replication_slots;