Subject: Re: DNAT sporadically doesn't replace destination IP address

From: Patrick McHardy <[email-masked]>
Date: Thu, 22 May 2008 17:28:58 +0200

Kris Op de Beeck wrote:
> 
>>>> On 22/05/2008 at 16:57, in message <[email-masked]>, Patrick
> McHardy <[email-masked]> wrote:
>> Please try loading ipt_LOG and executing
>>
>> "echo 255 >/proc/sys/net/netfilter/nf_conntrack_log_invalid"
>>
>> and see if something shows up in the ringbuffer.
> 
> [  917.584000] nf_ct_tcp: invalid SYNIN= OUT= SRC=192.168.1.23 DST=10.9.9.22 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=3257 DF PROTO=TCP SPT=40018 DPT=80 SEQ=1136088214 ACK=0 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A00025B1C0000000001030307) UID=1000
> [  918.800000] nf_ct_tcp: invalid SYNIN= OUT= SRC=192.168.1.22 DST=10.9.9.21 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=26411 DF PROTO=TCP SPT=47713 DPT=80 SEQ=1041054567 ACK=0 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A00025C4C0000000001030307) UID=1000
> [  921.800000] nf_ct_tcp: invalid SYNIN= OUT= SRC=192.168.1.22 DST=10.9.9.21 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=26412 DF PROTO=TCP SPT=47713 DPT=80 SEQ=1041054567 ACK=0 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A00025F3A0000000001030307) UID=1000
> [  924.204000] nf_ct_tcp: invalid SYNIN= OUT= SRC=192.168.1.30 DST=10.9.9.29 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=25744 DF PROTO=TCP SPT=52775 DPT=80 SEQ=2154890499 ACK=0 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A000261930000000001030307) UID=1000
> [  927.204000] nf_ct_tcp: invalid SYNIN= OUT= SRC=192.168.1.30 DST=10.9.9.29 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=25745 DF PROTO=TCP SPT=52775 DPT=80 SEQ=2154890499 ACK=0 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A000264810000000001030307) UID=1000
> 
> For those DST ip addresses I've got failures

Which kernel is this test running on? That message
is gone since 2.6.22.