I need to get my wifi router to do port forwarding from internal LAN connections. The Port Forwarding feature of my router DIR-615 works as expected. I am having problem getting it to work within my LAN.

Lets start with some assumption

Wifi Router - LAN IP = Public IP : dynamic FTP server - LAN IP - : 21
My PC - LAN IP -
Dynamic DNS : username.dyndns.org

The Wifi router is set to forward Port 21 to . The connection to my FTP server works fine from connections outside my LAN (eg from work) by connecting to username.dyndns.org . But when I try FTP connection to username.dyndns.org from within my LAN here is what happens

Step 1 : It resolves the dynamic dns address to the router Public IP address.
Step 2 : Router figures it out as
Step 3 : the PC within the LAN tries to connect to to instead of

In my ideal situation, my Wifi router will do port forwarding from router ( from WAN as well as LAN. Currently, the port forwarding only works from WAN. The end objective is so that I can connect to the same address (username.dyndns.org) from both inside and outisde my LAN . If port forwarding don't happen within the LAN connections, this won't work.

This seems to be a router specific issue. I've had routers in the past that can do this. But my current router is does not have this ability (can't find a way to configure it either). Anyone here has a wifi router that don't have problems connecting to your servers within your LAN using dynamic dns address?


This is called hairpinning, and isn't supported very often by domestic routers.

The "easiest" way to your solution would be to run your own DNS server internally, and resolve username.dyndns.org to

  • Thank you for the answer. Now I know it's called hairpinning. I can google more about it. Thank you! – Gary Oct 11 '11 at 3:43
  • @Gary to thank Paul for his answer and indicate that it lead you to the solution, you should make sure to mark his answer as accepted using the checkmark button to the left. Just so you know, this site is different from regular forums: use comments for clarifications, etc. Answers are only for providing solutions to the problem. Cheers! – nhinkle Oct 11 '11 at 3:45
  • done! Sorry new to this :) – Gary Oct 11 '11 at 14:34

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