[flow-tools] flow-capture + misconfigured iptables = kernel panic

[Greg.Volk@edwardjones.com]

Just a heads up to anyone running flow-capture and iptables...

I managed to repeatedly kernel panic my linux 2.4.19 box by
launching flow-tools, and then blocking the UDP port that
it binds to with iptables. If done in the opposite order,
iptables, then flow-tools, the box won't panic, but you 
won't get any data if the UDP port is blocked.

Correctly configuring iptables to not block my flow-capture 
port results in no panics, and good data captured.

It only took me three kernel panics to realize what was
happening. ;)