bm
Go here..
http://www.traceroute.org/ chose a country that is not yours! and then try to do a trace to your domain.
eg - select one of the links and it will open up a traceroute form, slot in your domain name blahblah.com - and it will show you a "trace" from where it is to your server.
if it times out somewhere.. then there is a network problem.
Also do the same from your own PC..
at the MSDOS prompt(assuming windows?) type
traceroute yourdomain.com
and it should trace the route to your server... again if it times out somewhere it might show you where the problem is.
DD