What are the minimum network specifications?

You will need a cat5 (or higher) ethernet cable, as well as a simple switch. For very high performance systems, a gigabit switch is recommended.

Do I need a DHCP server?

No. Whenever a DHCP server is in the network, the anchors will retrieve their IP from it. Otherwise, the anchors will automatically select an IP in the range 169.254.x.x.