IP Masq'ing problem

[David Grill Watson <dgwatson@kent.edu>]

I have a very strange problem with IP  masquerading.  If I just set it up for 
basic access (nothing unusual, just masquerading for the in-house LAN thru my 
box which has a RoadRunner connection), everything is peacy - except that my 
brother can't play Jedi Knight over the 'net.

I know how to set it up to do that, and it's actually fairly simple:

/usr/sbin/ipmasqadm autofw -A -r udp 2300 2400 -h 192.168.0.6 
/usr/sbin/ipmasqadm autofw -A -r tcp 2300 2400 -h 192.168.0.6                 
 
(192.168.0.6 is his computer when it's in windows)

But that has one very obnoxious side affect - after a while (half an hour? an 
hour?), I can connect to no websites (it says it's contacting them, but no 
reply) from either the masq'ing box or machines behind it.  I can, however, 
use ICQ and ssh with no problems at all.

The problems don't go away if I stop the masquerading for those ports - and 
even if I unload the kernel module!  The only way I can fix it is to reboot.

If anyone has the slightest idea what might be the problem, please let me 
know - it's driving all of us nuts!

-DGW

PS: I'm using kernel 2.2.14, and the latest woody, just in case you want to 
know.