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I'm trying to log any requests to port 22 into my syslog, so I have following line in my iptables:

LOG        tcp  --  anywhere             anywhere            tcp dpt:ssh LOG level debug 

yet, when I ssh in, nothing gets logged. I'm using RHEL6 (6.2)

Any ideas why?

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don't just downvote! explain why! – alexus Nov 8 '12 at 16:30
up vote 3 down vote accepted

I've used the following to log new connections to port 22

iptables -I INPUT -p tcp -m tcp --dport 22 -m state --state NEW  -j LOG --log-level 1 --log-prefix "New Connection "

This rule only logs new connections to port 22. It logs to /var/log/messages on the CentOS box I have to hand

Nov 8 16:20:54 centos6 kernel: New Connection IN=eth0 OUT= MAC=00:0c:29:d2:2c:38:00:0c:29:fe:8e:bb:08:00 SRC= DST= LEN=52 TOS=0x00 PREC=0x00 TTL=126 ID=9880 DF PROTO=TCP SPT=63861 DPT=22 WINDOW=8192 RES=0x00 SYN URGP=0

Note that iptables actions rules in the order they are defined so if you used iptables -A to add your rule to an existing ruleset then it's possible that packets are being accepted or denied by an earlier rule and your log action is never erm actioned.

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that works, thank you so much! – alexus Nov 8 '12 at 16:31

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