* Re: do not understand these logged iptables packets
[not found] <5073A4E5.10406@comcast.net>
@ 2012-10-09 13:03 ` AJ Weber
2012-10-18 2:28 ` U.Mutlu
0 siblings, 1 reply; 2+ messages in thread
From: AJ Weber @ 2012-10-09 13:03 UTC (permalink / raw)
To: netfilter
> Sorry, I'm a bit of a novice with understanding the iptables logged
> output. I'm obviously rejecting some packets that don't appear to be
> generated by my server, yet they seem to indicate that they were
> generated by my server? I can not identify any process/daemon of mine
> that should be generating any of these entries.
>
> Do they look "familiar" to anyone? Are there any tools recommended to
> better determine what rule they're triggering or something?
>
> Thanks in advance,
> AJ
>
> Oct 8 22:22:41 servername kernel: [TCP reject] IN= OUT=eth0
> SRC=74.x.x.x DST=54.248.104.161 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
> DF PROTO=TCP SPT=80 DPT=50740 WINDOW=5 RES=0x00 ACK SYN URGP=0
> Oct 8 22:52:20 servername kernel: [TCP reject] IN= OUT=eth0
> SRC=74.x.x.x DST=1.34.22.39 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF
> PROTO=TCP SPT=1080 DPT=6000 WINDOW=5 RES=0x00 ACK SYN URGP=0
> Oct 8 22:57:35 servername kernel: [TCP reject] IN= OUT=eth0
> SRC=74.x.x.x DST=61.160.195.24 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
> DF PROTO=TCP SPT=1433 DPT=6000 WINDOW=5 RES=0x00 ACK SYN URGP=0
> Oct 8 23:06:34 servername kernel: [TCP reject] IN= OUT=eth0
> SRC=74.x.x.x DST=218.201.121.99 LEN=40 TOS=0x00 PREC=0x40 TTL=64 ID=0
> DF PROTO=TCP SPT=8080 DPT=3955 WINDOW=5 RES=0x00 ACK SYN URGP=0
> Oct 8 23:11:23 servername kernel: [TCP reject] IN= OUT=eth0
> SRC=74.x.x.x DST=58.218.199.227 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
> DF PROTO=TCP SPT=9000 DPT=12200 WINDOW=5 RES=0x00 ACK SYN URGP=0
> Oct 8 23:11:23 servername kernel: [TCP reject] IN= OUT=eth0
> SRC=74.x.x.x DST=58.218.199.227 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
> DF PROTO=TCP SPT=2479 DPT=12200 WINDOW=5 RES=0x00 ACK SYN URGP=0
> Oct 8 23:11:23 servername kernel: [TCP reject] IN= OUT=eth0
> SRC=74.x.x.x DST=58.218.199.227 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
> DF PROTO=TCP SPT=8118 DPT=12200 WINDOW=5 RES=0x00 ACK SYN URGP=0
>
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: do not understand these logged iptables packets
2012-10-09 13:03 ` do not understand these logged iptables packets AJ Weber
@ 2012-10-18 2:28 ` U.Mutlu
0 siblings, 0 replies; 2+ messages in thread
From: U.Mutlu @ 2012-10-18 2:28 UTC (permalink / raw)
To: netfilter
AJ Weber wrote, On 10/09/2012 03:03 PM:
>> Sorry, I'm a bit of a novice with understanding the iptables logged output. I'm obviously rejecting some
>> packets that don't appear to be generated by my server, yet they seem to indicate that they were generated
>> by my server? I can not identify any process/daemon of mine that should be generating any of these entries.
>>
>> Do they look "familiar" to anyone? Are there any tools recommended to better determine what rule they're
>> triggering or something?
These are standard LOG results, here specified for invalid tcp state, ie. unexpected ACK SYN packets.
Here's a slightly different example for the INPUT chain (yours is for OUTPUT I think):
iptables -A INPUT -p tcp --tcp-flags RST RST -m state --state INVALID -j LOG --log-prefix "[TCP reject]"
>> Thanks in advance,
>> AJ
>>
>> Oct 8 22:22:41 servername kernel: [TCP reject] IN= OUT=eth0 SRC=74.x.x.x DST=54.248.104.161 LEN=40 TOS=0x00
>> PREC=0x00 TTL=64 ID=0 DF PROTO=TCP SPT=80 DPT=50740 WINDOW=5 RES=0x00 ACK SYN URGP=0
>> Oct 8 22:52:20 servername kernel: [TCP reject] IN= OUT=eth0 SRC=74.x.x.x DST=1.34.22.39 LEN=40 TOS=0x00
>> PREC=0x00 TTL=64 ID=0 DF PROTO=TCP SPT=1080 DPT=6000 WINDOW=5 RES=0x00 ACK SYN URGP=0
>> Oct 8 22:57:35 servername kernel: [TCP reject] IN= OUT=eth0 SRC=74.x.x.x DST=61.160.195.24 LEN=40 TOS=0x00
>> PREC=0x00 TTL=64 ID=0 DF PROTO=TCP SPT=1433 DPT=6000 WINDOW=5 RES=0x00 ACK SYN URGP=0
>> Oct 8 23:06:34 servername kernel: [TCP reject] IN= OUT=eth0 SRC=74.x.x.x DST=218.201.121.99 LEN=40 TOS=0x00
>> PREC=0x40 TTL=64 ID=0 DF PROTO=TCP SPT=8080 DPT=3955 WINDOW=5 RES=0x00 ACK SYN URGP=0
>> Oct 8 23:11:23 servername kernel: [TCP reject] IN= OUT=eth0 SRC=74.x.x.x DST=58.218.199.227 LEN=40 TOS=0x00
>> PREC=0x00 TTL=64 ID=0 DF PROTO=TCP SPT=9000 DPT=12200 WINDOW=5 RES=0x00 ACK SYN URGP=0
>> Oct 8 23:11:23 servername kernel: [TCP reject] IN= OUT=eth0 SRC=74.x.x.x DST=58.218.199.227 LEN=40 TOS=0x00
>> PREC=0x00 TTL=64 ID=0 DF PROTO=TCP SPT=2479 DPT=12200 WINDOW=5 RES=0x00 ACK SYN URGP=0
>> Oct 8 23:11:23 servername kernel: [TCP reject] IN= OUT=eth0 SRC=74.x.x.x DST=58.218.199.227 LEN=40 TOS=0x00
>> PREC=0x00 TTL=64 ID=0 DF PROTO=TCP SPT=8118 DPT=12200 WINDOW=5 RES=0x00 ACK SYN URGP=0
>>
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[not found] <5073A4E5.10406@comcast.net>
2012-10-09 13:03 ` do not understand these logged iptables packets AJ Weber
2012-10-18 2:28 ` U.Mutlu
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