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DHCP lease expires and Tomato doesn't grab new IP?

Discussion in 'Tomato Firmware' started by gordo_1, May 20, 2008.

  1. gordo_1

    gordo_1 Network Guru Member

    For some reason, when my ISP changes my external IP address (which happens frequently on my DSL line), Tomato 1.19 doesn't seem to grab the new IP, and just reads zeros for remaining lease time. I can manually force it to update by clicking on "Renew", but it doesn't automatically seem to do it consistently. This prevents me from accessing my machines remotely as I rely on Tomato to update my DynDNS provider (which otherwise works flawlessly). Any ideas why this would be happening or how I can fix it?

    Screenshot of expired DHCP lease:
  2. Victek

    Victek Network Guru Member

    Give a try to the mod version 1.19.88xx from my post, I would like to know the behaviour of the IP WAN DHCP module, please feedback your experience. I'm sure it will help all of us.

  3. mstombs

    mstombs Network Guru Member


    The dhcp lease should be renewed when 50% of the lease expired. You say you have DSL - does that mean your DSL modem is running in half-bridge mode with very short lease times? I believe udhcpc gives up if it fails 3 times.


    Yes this very problem occured when Jon tried to upgrade to busybox 1.9, would be good for all of us if the new 1.10.2 fixes this problem!
  4. bigclaw

    bigclaw Network Guru Member

    Your connection type says DHCP, that means your router is obtaining its IP from the modem, not your ISP. A remaining DHCP lease time of 0 means the lease time is infinite.

    You are probably better off running the modem in bridged mode and let the router handle the PPPoE connection. This solves the DHCP problem as well as other potential headaches down the road.
  5. roadkill

    roadkill Super Moderator Staff Member Member

    It's not busybox that was modified for dhcp to work, it's Tomato's dhcp service.
  6. mstombs

    mstombs Network Guru Member

    Isn't udhcpc provided by BusyBox? Or do you mean the bug was in the way Tomato started the service?
  7. gordo_1

    gordo_1 Network Guru Member

    My modem is currently doing PPPoE and the WRT54GL router DHCPs the IP from the modem. I can certainly put the modem in bridge mode and do PPPoE on the router, but I've never had to do that in the past... Won't that put undue stress on the router, which is already doing QoS as well?
  8. roadkill

    roadkill Super Moderator Staff Member Member

    [B]release/src/router/rc/dhcp.c[/B] tomato v1.19 line 310
            "-i", ifname,
            "-s", "dhcpc-event",
            argv[0], argv[1],    // -H wan_hostname
            argv[2],            // -m
            argv[3],            // -Q
            argv[4], argv[5]    // -l lan_ifname
    the -l and -m parameters don't exist in udhcpc so dhcp doesn't function
    we just commented those parameters and everything started to work.

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