I am new to security, some one asked me this question. I thought you can help me.

Perimeter device identification

>> When ping is not working in the destination, and when you dont know the server is on/off, what do you do?

Try to
Telnet 21,23,25,80,110 etc.,
try nmap with various types of port scannig.,
try sniffing if it is local network and IDS is not present.,

If the the target is away in a different network with perimeter device installed, how do you find wether it is ON/OFF & the periemter device which is protecting it?

Is there any tool or tutorial, if there is something please help me.

anban