[Answer ID: 14761]

How to: Verify or test port forwarding setup ?

Created 10/04/2012 05:28  |   Updated 10/12/2012 07:27



Port forwarding setup on AirStation  router can be verifird in one of the following ways :


1) start the server (server process/service) on the PC/LAN side.

you can use Netcat to simulate a server. Issue the following command on server PC :

 nc -l -p  LAN_side_PORT

For example, if you have web server running on port 81, you can simulate a server by issuing the following command:

nc -l -p 81


2)  Next, you have the following options to initiate a connection from external network to the WAN port.

A. use a web based port scanning tool provided by any 3rd party such as the following for example  :



B. Alternatively, use Netcat software to connect or scan a range of ports on WAN side.

 Issue,  from a host outside your LAN network through WAN/Internet connection the following command:

echo hello | nc server_public_IP WAN_port


telnet server_public_IP WAN_port


A successful connection from a host outside the network  to the server/PC is a confirmation that port forwarding setup is correct. 


Trouble Shooting

Check firewall settings on both client and server PCs :

to check firewall on your PC is not blocking the port,  run Netcat as server and send an echo command from another command console on the same PC :

   A) server on console#1: nc -l -p 8181

   B) on same PC, client on console#2: echo hello | nc 8181

if you do not see the hello mesage on console 1, this means the port is blocked. change firewall settings to unblock the port.






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