I have two servers, 198.162.0.4 and 198.162.0.10, that were connected across a LAN. They are the components of a DMZ where 198.162.0.4 is the wen server and 198.162.0.10 the application server. 198.162.0.4 is running Ubuntu 11.04 while 198.162.0.10 is running Ubuntu 11.10. I had to restart 198.162.0.10 because Unity froze up. (I have since replaced it with Gnome.) Ever since I started it up again, I cannot get connectivity with 198.162.0.4. When I try

ping 192.162.0.4
I get

PING 192.162.0.4 (192.162.0.4) 56(84) bytes of data.

That is, it just hangs. I get the same result if I try

ping 192.162.0.10

on 192.162.0.4.

I had been saving my iptables in iptables.save but now I see that that fie is of zero size for some reason although I had a lot of rules in the IPtable. I tried to fix the problem with

sudo iptables -A OUTPUT -s 192.162.0.4 -j ACCEPT
sudo iptables -A OUTPUT -d 192.162.0.4 -j ACCEPT
sudo iptables -A INPUT -s 192.162.0.4 -j ACCEPT
sudo iptables -A INPUT -d 192.162.0.4 -j ACCEPT

but it has no effect.

Any assistance would be most appreciated,
Peter.