This program is an extension of the gethostbyaddr() function in the C library. I wrote this because I supposedly know some hostnames that I shouldn't know. So now I can get the name of all the hosts that have PTR records in the DNS server.

Command syntax:

• gethostsbysubnet
• gethostsbysubnet 10.72.63.12
• gethostsbysubnet 10.36.35.123/255.255.0.0
• gethostsbysubnet 10.0.0.5/24