[lug] ipchains and SYN packets

D. Stimits stimits at idcomm.com
Sun Jan 20 15:25:17 MST 2002


I found a nasty problem in RH 7.1, that syslogd tries to restart 6 times
when it comes to its time (via cron I assume). Doing certain things at
exactly the time of the restart is fatal, such as shutdown or restarting
xinetd. I lost my entire ipchains rule set, aside from an old backup (I
do not use iptables, I use ipchains). Now I'm trying to figure out some
old rules, and having no luck with SYN packets. I should be able to deny
all incoming ssh port 22 packets that are SYN packets with the -y or
--syn, but this does not work, it kills my script. If -y and --syn are
no longer used on ipchains (not iptables), how do I specify syn packets?
Consider the abbreviated lines that RH uses in /etc/sysconfig/ipchains,
I can deny all input of ssh port via:
-A input -s 0/0 -d 127.0.0.1/8  -i ppp0  -j DENY

I want to deny SYN packets only though, any suggestions? -y and --syn
cause failure, at least in the variations I tried.

D. Stimits, stimits at idcomm.com



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