Add NAT support.

docs/HowTo/Find-and-Connect/Specifying-NAT.md

@@ -24,19 +24,10 @@ device.
     UPnP support is often disabled by default in networking firmware. If disabled by default, you
     must explicitly enable UPnP support.
 
-!!! important
-
-    When the NAT method is set to `UPNP`, the advertised port is the same as the
-    [listening port](../../Reference/CLI/CLI-Syntax.md#p2p-port).
-
 ## None
 
 Specify `NONE` to explicitly configure the external IP address and ports advertised using
-[`--p2p-host`](../../Reference/CLI/CLI-Syntax.md#p2p-host) and
-[`--p2p-port`](../../Reference/CLI/CLI-Syntax.md#p2p-port) for the P2P service.
-
-!!! important
+[`--p2p-advertised-ip`](../../Reference/CLI/CLI-Syntax.md#p2p-advertised-ip) and
+[`--p2p-advertised-port`](../../Reference/CLI/CLI-Syntax.md#p2p-advertised-port) for the P2P service.
 
-    When the NAT method is set to `NONE`, the advertised port is the same as the
-    [listening port](../../Reference/CLI/CLI-Syntax.md#p2p-port). Manual configuration of your
-    firewall may be required to allow external hosts to create inbound connections to Teku.
+Manually configure your firewall to allow external hosts to create inbound connections to Teku.

docs/Reference/CLI/CLI-Syntax.md

@@ -1089,7 +1089,11 @@ List of comma-separated Ethereum Node Records (ENRs) for P2P discovery bootstrap
     p2p-advertised-port: 1789
     ```
 
-The advertised P2P port. The default is the port specified in [`--p2p-port`](#p2p-port)
+The advertised P2P port. The default is the port specified in [`--p2p-port`](#p2p-port).
+
+The advertised port can differ from the [`--p2p-port`](#p2p-port). For example, you can set the
+advertised port to 9010, and the `--p2p-port` value to 9009, then manually configure the firewall to
+forward external incoming requests on port 9010 to port 9009 on the Teku node.
 
 ### p2p-private-key-file