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Neighbour table overflow - Conntrack Settings

Discussion in 'Tomato Firmware' started by rizsher, Mar 23, 2008.

  1. rizsher

    rizsher Network Guru Member

    With Azureus running on a dedicated machine, IP address (both Src AND Dst) set to Lowest Priority, With attached Conntrack Settings, I get the following entries in my Tomato 1.11 logs:

    Mar 23 19:41:41 MyRouter local0.info udhcpc[252]: Lease of xx.xx.xx.xx obtained, lease time 114
    Mar 23 19:41:42 MyRouter user.warn kernel: NET: 38 messages suppressed.
    Mar 23 19:41:42 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:41:47 MyRouter user.warn kernel: NET: 17 messages suppressed.
    Mar 23 19:41:47 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:41:52 MyRouter user.warn kernel: NET: 31 messages suppressed.
    Mar 23 19:41:52 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:41:57 MyRouter user.warn kernel: NET: 40 messages suppressed.
    Mar 23 19:41:57 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:02 MyRouter user.warn kernel: NET: 53 messages suppressed.
    Mar 23 19:42:02 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:24 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:24 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:24 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:24 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:27 MyRouter user.warn kernel: NET: 29 messages suppressed.
    Mar 23 19:42:27 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:35 MyRouter user.warn kernel: NET: 27 messages suppressed.
    Mar 23 19:42:35 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:38 MyRouter local0.debug udhcpc[252]: Sending renew...
    Mar 23 19:42:38 MyRouter local0.info udhcpc[252]: Lease of xx.xx.xx.xx obtained, lease time 114
    Mar 23 19:42:40 MyRouter user.warn kernel: NET: 8 messages suppressed.
    Mar 23 19:42:40 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:42 MyRouter user.warn kernel: NET: 9 messages suppressed.
    Mar 23 19:42:42 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:50 MyRouter user.warn kernel: NET: 27 messages suppressed.
    Mar 23 19:42:50 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:53 MyRouter user.warn kernel: NET: 28 messages suppressed.
    Mar 23 19:42:53 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:42:59 MyRouter user.warn kernel: NET: 25 messages suppressed.
    Mar 23 19:42:59 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:30 MyRouter user.warn kernel: NET: 15 messages suppressed.
    Mar 23 19:43:30 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:30 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:31 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:32 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:32 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:32 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:32 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:35 MyRouter local0.debug udhcpc[252]: Sending renew...
    Mar 23 19:43:35 MyRouter local0.info udhcpc[252]: Lease of xx.xx.xx.xx obtained, lease time 114
    Mar 23 19:43:37 MyRouter user.warn kernel: NET: 34 messages suppressed.
    Mar 23 19:43:37 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:42 MyRouter user.warn kernel: NET: 32 messages suppressed.
    Mar 23 19:43:42 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:47 MyRouter user.warn kernel: NET: 43 messages suppressed.
    Mar 23 19:43:47 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:52 MyRouter user.warn kernel: NET: 41 messages suppressed.
    Mar 23 19:43:52 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:43:57 MyRouter user.warn kernel: NET: 37 messages suppressed.
    Mar 23 19:43:57 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:32 MyRouter local0.debug udhcpc[252]: Sending renew...
    Mar 23 19:44:32 MyRouter local0.info udhcpc[252]: Lease of xx.xx.xx.xx obtained, lease time 114
    Mar 23 19:44:42 MyRouter user.warn kernel: NET: 57 messages suppressed.
    Mar 23 19:44:42 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:42 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:42 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:43 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:44 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:44 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:44 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:44 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:45 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:48 MyRouter user.warn kernel: NET: 3 messages suppressed.
    Mar 23 19:44:48 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:52 MyRouter user.warn kernel: NET: 26 messages suppressed.
    Mar 23 19:44:52 MyRouter user.warn kernel: Neighbour table overflow.
    Mar 23 19:44:57 MyRouter user.warn kernel: NET: 23 messages suppressed.
    Mar 23 19:44:57 MyRouter user.warn kernel: Neighbour table overflow.

    I don't knw if this is related, but I get random disconnects on the extensions registering wiht a Asterisk server connected to the same router. Does the "Neighboug Table Overflow" entry mean the conntrack settigs are incorrect?.
     

    Attached Files:

  2. mstombs

    mstombs Network Guru Member

    The Neighbour table is the "arp table", look at the "device list" in the web gui. You are obviously using a modem running a horrible version of half-bridge called "ZIPB" (used by D-Link UK in the DSL320T for example), the very short lease time is another give away. ZIPB gives the router the same IP address for both IP and Gateway. This has the effect of making it appear that every address on the internet is local - easy to overflow the 256 (or similar) limit.

    What modem are you using? Can you switch to PPPOE full bridge?
     
  3. rizsher

    rizsher Network Guru Member

    Thanks for the reply Tombs. I'm in the UK, I don't think PPPoE is an option for me.... I use an ADSLNation X-Modem, which is supposed to be a very reputable British manufacturer, utilising what they call "Live IP", according to them:

    I've never had a problem with the modem. As a test, I closed all instances of Azureus, and after a few hours, looked at the logs again, in a siz hour period, there wasn't a single Neighbour Table Overflow entry.

    ...... any other ideas?
     
  4. mstombs

    mstombs Network Guru Member

    The arp-table only has a 5 minute memory, you just need to limit the number of connections Azureus is allowed to use.

    The crazy thing about this method of half-bridge is that all the entries will in the arp table will have the same modem MAC address. For every internet IP address that the router wants to communicate with it send out an arp "who has", and the modem replies "I do...".
     

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