From mboxrd@z Thu Jan 1 00:00:00 1970 From: "U.Mutlu" Subject: Re: do not understand these logged iptables packets Date: Thu, 18 Oct 2012 04:28:23 +0200 Message-ID: <507F6947.1020903@mutluit.com> References: <5073A4E5.10406@comcast.net> <50742084.7080802@comcast.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <50742084.7080802@comcast.net> Sender: netfilter-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: netfilter@vger.kernel.org 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 >>