Click
Start-->Run and in the "Open" prompt type
cmd and click "OK".
From the command prompt use
telnet to diagnose a port issue:
Command:
telnet <ip> <port>
Example:
telnet 123.123.123.123 80
First try your router's IP...you know you have connectivity on that port if you get a blank screen with a cursor flashing...if you get a "could not connect" then a firewall or network configuration is blocking port 80 (http) traffic thus causing your browser sessions to fail. By telnetting a server on port 80 you are mimicing how your browser taps into a webserver to display pages. IF you cannot do this then there is a misconfigured firewall or network rule somewhere between your hosts and the Internet. First you would check the router for a proxy address or "http restrictions" and disable them if present. If there's nothing in the router then you should try bypassing the router and plugging one of the computers directly into the DSL. If you can hit web pages when directly in then you know it's the router. IF you still cannot hit pages then double check to make sure there aren't any firewalls running on the computer. If you are certain there are no firewalls and you still can't hit pages even when directly attached to the DSL then there is a chance the provider somehow provisioned your DSL to have port 80 traffic blocked. I have worked for very large ISPs in the past I have seen it happen where a specific port is blocked for a small number of IPs. This is a rare configuration error - doesn't happen very often. Some ISPs will block certain ports if they see viral traffic from your hosts/network...you may want to check with the ISP to be sure this isn't your problem. Another thing to ask if if they require you to use a proxy or if they are running transparent proxies...they usually won't want to tell you this. Either way you could check for a "NAT" setting in that SMC and enable it as this may fix a problem with a transparent proxy. I really don't think that's the problem but I've seen weirder things. Good luck!
Unsolved 
