Snort mailing list archives
Re: OT: Deciphering log entry(iptables)
From: Matt Kettler <mkettler () evi-inc com>
Date: Tue, 02 Apr 2002 13:54:33 -0500
You said there was no outbound syn packet.. but in this case I suspect there would be an *inbound* syn...
This would appear that someone tried to connect to a webserver on your machine, and your machine responded with a reset since it was not running one.
This is extraordinarily common due to the number of web-server infecting worms floating around.
typical expected sequence to generate this: someone:someport -> you:80 syn you:80 -> someone:someport rst - "get lost buddy." or possibly:someone_running_portscaners:someport -> you:80 (no flags, fake fin/ack, or a xmas tree)
you:80 -> someone:someport rst - "get lost buddy."Of course what kinds of traffic would generate a RST instead of an ICMP error message will vary with how you have iptables configured.
At 09:24 AM 4/2/2002 -0800, you wrote:
This isn't related to snort (yet) I havn't installed it on this network. I was going through my log files on this firewall and have a ton(literally) of this entry. The only thing that changes is the destination ip's last two octets. eth0 is the external interface. There is no initiating SYN packet out bound.(that I know of need to run tcpdump on it for a bit) Has anyone seen this or know what it may be related to? Mar 31 04:19:35 xxxxfw1 kernel: IN= OUT=eth0 SRC=aa.bb.cc.ddd(me) DST=aa.bb.ee.ff(them) LEN=40 TOS=0x00 PREC=0x00 TTL=255 ID=0 DF PROTO=TCP SPT=80 DPT=2418 WINDOW=0 RES=0x00 ACK RST URGP=0 Cheers, Scott Oh yea, I think this is good for a drink or possibly two. THERE IS ONLY ONE... SOCCER.COM, The Center of the Soccer Universe http://www.soccer.com _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users
_______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users
Current thread:
- OT: Deciphering log entry(iptables) Scott Taylor (Apr 02)
- Re: OT: Deciphering log entry(iptables) Matt Kettler (Apr 02)
- Re: OT: Deciphering log entry(iptables) Chris Green (Apr 02)
- Re: OT: Deciphering log entry(iptables) Matt Kettler (Apr 02)