Posts: 3
Registered: ‎12-23-2008
Accepted Solution

WRT54G v7 WAN DHCP client problem

I've recently started having a strange problem with my WRT54G. Internet access is via a Cable modem and has been working fine for months, and the cable modem works fine so I suspect the problem is with the router. However the router is also working, mostly, so I figured I'd see if anyone here has any suggestions. Here are the details of the problem:


  • The router WAN configuration was set to DHCP.
  • It used to happily pick up a new IP address from the cable modem whenever necessary.
  • One night the router stopped picking up an IP on the WAN side. (nothing was changed. I'm the only one in the house who goes anywhere near the router)
  • Connecting the modem directly to a PC works fine (suggesting the modem's DHCP server is fine).
  • Copying the WAN IP config from the PC to the router, as a Static IP, also allows it to work when the modem is plugged back into the router and the router to a PC (which is how it's setup now, but it's a pain to have to mess with the physical connections and manually reconfigure the router every time the modem drops a connection (which is another issue, but not one for this forum...)).


So both the modem and the router seem to work except for the router's DHCP client. It works fine as a DHCP server for the LAN.


The firmware was already upgraded (and working), I've followed the standard power-cycle procedure, I've released and renewed the IP via the Status tab in the web interface, and I've tried resetting the router using both the button on the unit and via the web interface to revert to factory defaults.


Any suggestions?

Posts: 2,653
Registered: ‎09-07-2006

Re: WRT54G v7 WAN DHCP client problem

If u have upgraded the firmware of the Rotuer and also reseted the Router.

So what u do is- Open the Setup page of the Rotuer and admin as the password.

Changed the Internet Connection type to DHCP and then changed the MTU to Manual and size to 1364 save settings.

Then checked the WAN IP if its Click on the Setup tab and then click on sub tab Mac Address Clone-check the Enable box-then click on clone your PC's Mac-then Save settings-checked the WAN IP if the Network-Means Unplug the Power cable of the Router and the Modem and Plug it back in after 30 secs.

When you plug back make sure you plug the Modem first and then the Router.

Check whether u are able to online or not.


Posts: 3
Registered: ‎12-23-2008

Re: WRT54G v7 WAN DHCP client problem

Seems the MTU change did the trick. Thanks saber_tooth!
Posts: 1
Registered: ‎12-27-2008

Re: WRT54G v7 WAN DHCP client problem

I also had this problem which occurred after >2 years of the router working fine.  After changing MTU to 1300, cloning the PC MAC address, and power cycling the router and modem fixed the problem.  But I was curious to see which change did the trick, so I changed both back to the default (MTU = auto and not cloning the MAC address) and it worked fine!  I think the router problem is intermittant and may appear to be fixed by changing setting, but I fully expect it to reoccur. 
Posts: 3
Registered: ‎12-23-2008

Re: WRT54G v7 WAN DHCP client problem

Ah, I see you're right. Hmm. Well, guess I won't worry about it unless it does happen again and the same fix doesn't work.