Tracking Routed Connections
Netstat is great for looking at connections between a given local machine and remote machines, but about connections that a machine is acting as a router for, as in the case of a Linux box running Netfilter/IPTables? The Perl script linked does just that, by parsing /proc/net/ip_conntrack into an easily readable form, complete with reverse lookups on IP addresses.
I had posted this earlier with a link to the author’s original version, but apparently, that one doesn’t work very well. This one has the bugs fixed, and is the one I originally came across.
