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  1. #1

    iptables logging on Damn Small Linux

    I am in the process of setting up some iptables chains for our EMS device that runs DSL linux and I am experiencing some slowdowns on my ssh log in when it prompts for password.

    After some searching it was suggested i was seeing a reverse DNS timeout and if I open UDP 53 out it should fix this. Now this was true, it did fix the ssh log in slow down on an Ubuntu machine that was acting the same way, but when I ported the new findings to our EMS device I still saw the same slowdowns on the return prompt asking for password (almost 20 seconds)

    I fig the best way to see whats going on is to log it all. I cleared the ipchains and used the following commands:

    iptables -A OUTPUT -j LOG
    iptables -A INPUT -j LOG
    iptables -A FORWARD -j LOG

    I then made sure syslogd was up and running and it is in fact logging message to the /var/log/message file but just the standard logs not iptable traffic logs.(for example I can see it logging my ssh sessions and me restarting syslog)

    Once again I got this working on Ubuntu but Im at a loss here. Does anyone have an suggestions on where I can look to troubleshoot this error or is there some info i could provide that may help you.

    edit: I also tried adding "kern.warning /var/log/iptables.log" to the /etc/syslog.conf file and added --log-level 4 to my iptables log statements above but alas the iptables.log file is not created when I restart syslogd and if I touch them manually they still stay empty.

  2. #2
    TCP 113 - Port Protocol Information and Warning!

    Turns out the SSH slowdown was because I needed to allow outgoing TCP 113. I still cant fix the logging problem so I just input outbound rules allowing port ranges and then checked ssh login time and then proceeded to half the range each time I reset the rules untill I narrowed it down.

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