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Discussion in 'Tomato Firmware' started by polilla, Mar 9, 2010.

  1. polilla

    polilla LI Guru Member

    Some of my computers flooding router log like this:

    Mar 9 15:12:54 Linksys daemon.info dnsmasq-dhcp[27490]: DHCPINFORM(br0) xx:xx:xx:xx:xx:xx
    Mar 9 15:12:54 Linksys daemon.info dnsmasq-dhcp[27490]: DHCPACK(br0) xx:xx:xx:xx:xx:xx Andre

    Every 1 to 3 minutes my router receive this message.
    What can i do? Anyone know what is the problem?

    DHCP is enabled but the rest of the computers here ask router when needed, not spamming router-log.
  2. uscallesen

    uscallesen Addicted to LI Member

    Probably a defective dhcp implementation in one of your client devices - Which device/OS is it ?
  3. polilla

    polilla LI Guru Member

    Windows 7
  4. HennieM

    HennieM Network Guru Member

    It seems your computer, named Andre, is trying to tell Tomato's DHCP server:

    "Hi, I'm and I'm called Andre. Register my name and IP address on your DNS server so other machines can contact me by IP address or name"

    but Tomato's DHCP server is:
    i) not recognizing the register request, and thus sends no reply or a bogus reply back to Andre, and Andre then keeps on trying to register every few minutes, or
    ii) recognizing the request, and attempting to do the registration on DNS, but Andre in turn does not like or does not recognize that Tomato's DHCP server has acknowledged the request.

    Either way, one way to stop that is to turn off the "Register in DNS" on Andre's TCP/IP setup. (I dunno how to do that in Windoze 7).
  5. polilla

    polilla LI Guru Member

    First request of Andre is ok.
    "Hi here is MAC-Adress xx.xx... Do you habe some ip for me?"
    "Yes, here it is:, keep lucky within 24 hours"
    But now, this Computer don't stop bugging me in Tomatos-Log.
    Can anybody explain this, perhaps someone who knows how DHCP is working?
  6. Toastman

    Toastman Super Moderator Staff Member Member

    I see this often, the clients do seem to pick up an IP, but they don't stop polling. On XP, Win7, and Ubuntu. I've seen all of them do it, but have no idea why.
  7. mstombs

    mstombs Network Guru Member

    On windows XP it is something to do with "limited connection" detection, the OS seems to ping the dhcp server to make sure it has the right gateway.

    I've also seen it a lot with a Wii. I suspect the clients are objecting to some default firewall action?
  8. polilla

    polilla LI Guru Member

    Last night i checked his computer, everything was clean.
    Today his computer continuous polling router.
    Ask him what he do and he said playing Call of Duty:Modern Warfare 2.
    Running only this game with Steam and Skype is running for communication with his friend.
    For me it seems that one of this programs COD6, Steam or Skype is the problem.
  9. teddy_bear

    teddy_bear Network Guru Member

    Well, I don't use Skype or play Call of Duty or any other online games, but some wireless clients (with Atheros cards) on my home network generate these DHCP requests every 2 minutes spamming the log the same way, and I was unable to find any setting on the client to control that.

    It annoyed me so much that in my Tomato mod I added a new Dnsmasq setting. If you use this mod, you can put "quiet-dhcp" line into the "Dnsmasq Custom configuration" box, and it will stop logging these DHCP requests completely.
  10. Toastman

    Toastman Super Moderator Staff Member Member

    Aha, interesting! At the moment there is one guy polling every two minutes, there is also nothing apparently wrong with his PC, and it also uses atheros wireless.

    But - there are hundreds of atheros cards in these buildings, and they don't ALL do it. That's Odd!

    It would be interesting if you can get him to stop COD6, Steam and Skype for a while and see what happens. If it stops, then you should be able to see which one it is by starting them one at a time.
  11. HennieM

    HennieM Network Guru Member

    I would very much doubt that the continuous polling has anything to do with hardware, be-it Atheros or any other card. The DHCP communication, and, for that matter, all the talk after an IP address was obtained, is completely devoid of hardware dependance, and the sole result of the OS's TCP/IP software stack. I.e. if the PC could get an IP address, and speaks IP, that's confirmation that the hardware works, and that's already beyond hardware influence.

    I have seen this kind of (DHCP spam) behaviour on wired and wireless clients - the wireless with different cards talking to different APs. I just never cared enough to stop and find out exactly what the problem was.

    One thing that I do recall that seemed to work, was to always use fully qualified domain names on the host PCs; i.e. dynamic hosts get an IP, a name, and a domain, so Andre would be Andre.hennies.net, where hennies.net is the domain. Then, in Windoze, set the network-TCP/IP properties to register the fully qualified name in DNS, OR, turn off name registration completely.

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