DDNS sometimes gets updated with private!!

Discussion in 'Tomato Firmware' started by rizsher, Oct 17, 2007.

  1. rizsher

    rizsher Network Guru Member

    Using a modem in DHCP spoof mode which passes the public IP from the ISP to the WAN of WHR-HP-G54 running Tomato version 1.07.

    Every now and then, very rarely, but not rarely enough, my Dyndns.com host gets updated with a local private IP of instead of the public IP pulled from the ISP. It usually hapens when I power cycle the router or the modem. It wouldn't be too much of a problem, except all my home phone lines are VoIP thru an Asterisk server and the moment this happens, all phones either go down, and start 1 way audio.

    Is there something that can be done, maybe add a check such that private IPs, (10.0.x.x, 192.x.x plus others if there are) don't update ddns, but get flagged for another check in, say 2-3 minutes, by which time the router/modem have stabilised?.

  2. roadkill

    roadkill Super Moderator Staff Member Member

    half bridge dsl modem tend to do those things you probably got dhcp spoofing configured on the modem or something like that.
    you can use DDNS external IP checker to solve that.
  3. Macskeeball

    Macskeeball LI Guru Member

    Yes, update your Tomato firmware. The latest version at this time is 1.10, and it has what roadkill mentioned.
  4. mstombs

    mstombs Network Guru Member

    The router should only get a local IP address from the half bridge modem when the modem doesn't have internet access, so shouldn't be able to update dyndns! Voip phones also won't work because the internet connection is down.

    Is the bug that the ddns service keeps trying to send the local IP address and misses the change to the real WAN address completely?

    I would also say that the ddns should not try to update with a known local IP address, and the dyndns service should not accept it!

    Certainly worth trying with latest Tomato which has new ddns engine.
  5. roadkill

    roadkill Super Moderator Staff Member Member

    could be that the DSL modem is configured with a dhcp spoof that gives out a 10.0.0.X address when connectivity is down...
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