lkml.org 
[lkml]   [2005]   [Sep]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectIntermittent NAT failure when multiple hosts send UDP packets
    This smells like a bug in UDP ip_nat_proto_udp.c or nearby.
    I'm seeing this on 2.6.12-1.1447_FC4, but code in 2.6.13 is
    still the same.

    I've setup SNAT the usual way:

    iptables -A POSTROUTING -t nat -o ppp0 -j SNAT --to-source 151.38.19.110

    When multiple clients in the LAN send UDP packets to the same port of
    the same remote host, I see something like this in my /proc/net/ip_conntrack:

    udp 17 170 src=10.3.3.2 dst=194.185.88.60 sport=5060 dport=5060 src=194.185.88.60 dst=151.38.19.110 sport=5060 dport=5060 [ASSURED] use=1
    udp 17 29 src=10.3.3.2 dst=212.97.59.76 sport=5060 dport=5060 [UNREPLIED] src=212.97.59.76 dst=151.38.19.110 sport=5060 dport=5060 use=1
    udp 17 177 src=10.3.3.250 dst=194.185.88.60 sport=5060 dport=5060 src=194.185.88.60 dst=151.38.19.110 sport=5060 dport=1024 [ASSURED] use=1

    In the last line, the destination port has been properly remapped from
    5060 to 1024 to distingish between incoming packets.

    However, I see packets going out over ppp0 without the source
    address properly rewritten to 151.38.19.110:

    04:38:28.739514 IP 10.3.3.2.5060 > 194.185.88.60.5060: UDP, length 536

    This doesn't happen when there's just a single host sending to port 5060.
    Sometimes I must restart the interface to trigger this bug.



    --
    // Bernardo Innocenti - Develer S.r.l., R&D dept.
    \X/ http://www.develer.com/

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-09-17 05:06    [W:0.020 / U:0.688 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site