Finding the Address of your DHCP Server

Firewalls and routers are often configured as DHCP servers by default. That can cause issues if you already have a server on your internal network. How do tell which DHCP server any given client is using?

Mac OS X:

$ ipconfig getpacket en0

Where en0 is your Ethernet interface (you might want en1 if you are using a wireless connection)

Windows:

ipconfig /all

Linux:

$ more /var/lib/dhcp3/dhclient.eth0.leases

Where eth0 is your Ethernet interface.