In my experience, nmap is a far more useful tool for troubleshooting connectivity than traceroute. Scan a host and see if the port you want is open. If not, the

In my experience, nmap is a far more useful tool for troubleshooting connectivity than traceroute. Scan a host and see if the port you want is open. If not, then "closed" versus "filtered" versus "host is unreachable" will give you an idea if the issue is the destination program isn't running, the firewall on the target (or possibly elsewhere in between) is blocking things, or the host's not available on the network, either because it's misconfigured, in a different subnet or VLAN or whatever, or shut down.