This morning I found a computer on my network with the ip 10.0.7.92. The ip range that my dhcp server is using is 10.0.0 and no changes have been made to in in months. Furthermore, this computers mac address is mapped in the server to be assigned a specifc ip address every time.

The only logical reason that I can think of is that someone set up a second dhcp server on one of there machines. I tried to google around too how to find dhcp servers on my network. i didnt' have any luck.


Does anyone know how to find every available dhcp server?

Secondly, is there a way to get a list of every mac address my computer can reach? I was thinking of making a script that clears the arp cache then pings every ip from 10.0* to 10.254*, then the same with 192.168 etc. Is there a better way of doing this?

try pinging 10.0.7.1 ?

Maybe this person set their comp up for a static IP on their own, and there is no DHCP server? just the first thoughts to come to my mind. If you go on a computer on the same network as the suspected dhcp server, try running dhclient and see which dhcp servers answer the client

The ARP cache will show every MAC address your computer can talk to. If you want to ensure it's populated with every MAC on your network try "nmap -sP 10.0.0.0/24" which will ping every host it canon the /24 network.