Description of Problem:
Set up Masq + port forwarding in rc.local:
---snip---
echo "NAT..."
/sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

EXT=194.xxx.xxx.xxx
INT=192.168.201.103
DPORT=6346

iptables -A PREROUTING -t nat -p tcp -d $EXT --dport $DPORT -j DNAT --to $INT:$DPORT
iptables -A OUTPUT -t nat -p tcp -d $EXT --dport $DPORT -j DNAT --to $INT:$DPORT

echo 1 > /proc/sys/net/ipv4/ip_forward
---end---

use the port forwarding for a while, watch it work fine (LimeWire on a win2k box)
kernel will hang, no oops, nothing in logs, nothing on screen. no response to pings

How Reproducible:
when running gnutella on a box behind the machine, It stays up maybe 5-20minutes.
when not running gnutella (but lots of other network traffic) it stays up indefinitely

Steps to Reproduce:
1. 
2. 
3. 

Actual Results:


Expected Results:


Additional Information:
Standard RH7.1 installation, all updates installed. Kernel "2.4.3-12 #1 Fri Jun 8 15:05:56 EDT 2001 i686 unknown"	
iptables-1.2.1a-1
50 ip aliases were present on eth1 (200-250), the box forwarded to, was on the subnet with eth1:201 as gateway