hi this is a little something i got for you
as long as you are connected to the network you can do an arp -a or -g at the windows command prompt.
if dhcp is disabled there will by all means be a default GW that allows you to reach the internet or the rest of the network.
this should work because arp maps IP to MAC, then after you get a single IP detect the class of IP eg. class A,B or C.
the ;)hardway is to ping all host with in the network or subnet
sorry if this is a long method but as a hacker(ethical) you must do what ever it take to get what you want.
hope this works if it doesn't please let me know.
NB:software tools were created by the human mind so you can think and create one for your self.
