I have installed a Linksys router recently. It is sharing 2+ comp using one external address. It is acting as a firewall so I'm very safe from hackers (except virus from e-mails). I'm able to use almost every internet applications. I'm even able to host a WarCraft III game by triggering the DMZ function to my IP. However, I can't fix ICQ. Friends can't access my shared folder, I can't access my friend's shared folder who's on a router.
After some searching through the web and testing, I found the solution. This is actually a BUG. I'm sure some of the people here are on a router and this will sure help them a lot.
http://tuneld.homeip.net/htm/icq/icqbug.htm
Follow the site above STEP BY STEP.
However change the following thing.
1) In the TCP ports, the site suggest you open 24500-24505. However, I suggest you change that you select a port between 1024-65535. So for example you select 1024, open 5 ports behind it, therefore 1024-1029.
Hope this will help.