Unable to ping external IP address

[scnguitar]

If I can't ping someone's public IP, does that mean their router is blocking ping requests? Because I know for a fact that they're online because we're chatting right now (IP is from direct connection on instant messenger, Pidgin displays it when you connect).

If we were not chatting right now, how would I check to see if they're online if they're not responding to ping requests?

[xtc46]

no ping reply means they have a firewall or router set to either drop the packet or not reply. What I would do is port scan the IP using something like NMAP.

Most people have some ports open for various things (games, software etc) so port scanning is the best bet. If its a business, ports 3389 (RDP), Port 80(http) port 25(smtp) port 21(ftp) port 110 (pop) will be open as many business' host their own email and need those open for email and webmail access as well as ftp access.

Also try the ports for go to my PC, VNC, port 8080 (default for most SoHo routers) etc.

A broad port scan will cover it all for you though.

[scnguitar]

I used the nmap GUI for Windows (Zenmap) and did an Intense scan, no ping scan and no ports were found open. :(