WRT54GC - DHCP problems

Discussion in 'Cisco/Linksys Wireless Routers' started by torfason, Jun 24, 2006.

  1. torfason

    torfason LI Guru Member

    I have a wrt54gc and two Dell laptops configured for DHCP in a very straightforward setup. WAN is wired, LAN is wireless. I have WPA security enabled. The laptops are configured to use DHCP, and for the most part it works.

    However, after reebooting the computer or connecting it to another network and back (so it needs to get a new IP address from the DHCP) server, the DHCP server does not respond, even if I see that I am connected to my wireless network.

    ipconfig -renew hangs until I get a "failed to connect to DHCP server". After reebooting the router (by pulling the plug) everything works OK. The laptops have no problems on other wireless networks. Rebooting the router is what I've been doing for some months now, and I've tried to change various settings on the router, but this problem persists. It is extremely annoying.

    I have a 1.02.5 firmware and not very enthusiastic about upgrading it since it seems the procedure is prone to killing the router.
  2. sildenafil

    sildenafil LI Guru Member

    I don't know if this would work, but maybe you should try to setup assigned IP for your notebooks in the router. you can set it up to assign fixed DHCP IP to the MAC address in the web-based utility. This way it doesn't need to recertify a new IP for your notebook for each boot.

    Alternatively, you can always setup fixed IP (instead of DHCP protocol) on your notebook. you just need to set it at the same subnet:
    i.e. router;
    your notebook: 192.168.1.xx/,

    although, then you will have to change your notebook connection setting whenever you leave the house...

    "failed to connect to DHCP server" sounds more like a general connection problem though.?
  3. torfason

    torfason LI Guru Member

    Thanks for your reply.

    Configuring the DHCP to use a fixed IP address through the router was indeed one of the things I tried, and that is how it is running now. When it works, it works fine: I get the preassigned IP address and all other configuration correctly. However, sometimes I get this failed to connect.

    Using a fixed IP is also a good idea, but not feasible for me, because of the frequent reconfiguring (rebooting the router seems less of a hassle).

    I'd be interested to hear if there are any general guidelines fo debugging stuff like this. The reason I suspect the DHCP is that all the network level data (SSID, connection strength and other information on the general tab for Wireless Connection Status) look fine. But I'm no expert and would like to explore other paths as well.
  4. sildenafil

    sildenafil LI Guru Member

    I am really no expert here...

    But, if it fails to connect, can you repair connection from your notebook? I am thinking potentially your notebook was still thinking it's connecting to something else and tries to connect to the wrong IPs.


    one way to test if it is *NOT* DHCP problem, is to manually configure your notebook for fixed IP (use the same one the DHCP assigned you), then turn off the DHCP on your router. If that solves the problem for good, then we know it'd DHCP. otherwise it would be something else...
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