DHCP

A DHCP server allows the client to get an IP address automatically without having to manually configure a static IP.

DHCP relay

DHCP relay listens to local broadcast messages from client and forwards these messages on another network towards the DHCP server. The DHCP server responds and the replies is then forwarded back to the client.

DHCP proxy

DHCP proxy is a fully-functional DHCP server and client built inside. The client establishes IP leases from the DHCP server on one interface, and then keeps these addresses in a pool. On another interface, the server side of the implementation provides leases to other machines using that pool.

Example

Cisco PIX/ASA Firewalls supports both method. Generally, the FW interface on which it behaves as a DHCP server has a dedicated, manually-configured address pool, and the only thing the proxy feature does is get configuration parameters from another upstream server.

Reference

[[Category: Terminology]]