Workaround: Fix dd-wrt Port Forwarding on Netgear WNDR3700 build 16785

So it would appear that is a bug in the dd-wrt build 16785 (and probably several versions older) on the Netgear WNDR3700.  Basically you can set as many Port Forwarding rules you want and they will not work.

The issue appears to stem from a loopback issue identified for r15760 and later.  The fix is described as here.  Once the actions are taken the port forwarding functions work!   There is a brief mention of this loopback issue on the dd-wrt Port Forwarding Troubleshooting guide, but it does not make mention of it’s prominence.

The Fix

  • Telnet to the router
  • If you are using the default 192.168.1.x subnet issue the following command:
iptables -t nat -I POSTROUTING -o br0 -s -d -j MASQUERADE
  • Otherwise issue the command:
LAN=`nvram get lan_ipaddr`/`nvram get lan_netmask`
iptables -t nat -I POSTROUTING -o br0 -s $LAN -d $LAN -j MASQUERADE


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This entry was posted on Monday, May 2nd, 2011 at 5:29 am and is filed under How To's, Technology. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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