first the basic stuff:
1. from your cilent PCs, check if they can ping your linux machine.
2. If your LAN is ok, follow the steps here to share the internet connection:
http://www.yolinux.com/TUTORIALS/Lin...rkGateway.html
I am giving the link as I am not familiar with the sharing wizard of Mandy.
in the above link, look for the dsl/cable section.
your client pcs can't browse? check if they can ping outside hostnames (like
www.yahoo.com) if they have some hostname problems, try the IP addresses. if they can ping the IPs, u have a DNS problem. The best way to solve this is to implement a local dns forwarder via the named.conf file (u need the DNS ip adds of your ISP).
hth.