What term describes a host that relays DHCP requests and responses between a remote DHCP server and the client?

• A. DHCP Relay Agent
• B. Dial-ups
• C. Differential Backup
• D. DNS Poisoning

Answer: (A)

DHCP relay agents enable clients on one subnet to obtain IP configuration from a DHCP server on another subnet by forwarding DHCP messages between them. When a client on the local network broadcasts a DHCPDISCOVER to find a server, a device configured as a DHCP relay agent intercepts that broadcast and forwards it to the remote DHCP server, typically using UDP to port 67 on the server. The server replies with a DHCPOFFER (and later DHCPREQUEST, DHCPACK), and the relay agent forwards those responses back to the client, completing the exchange across subnets. In many networks, routers perform this relay function (often called an IP helper or DHCP relay), and they may also supply client location information via the DHCP relay information option to help the server allocate the correct address and settings.

Dial-ups, differential backups, and DNS poisoning aren’t involved in this process. Dial-ups are a means of remote access, differential backups are a backup method, and DNS poisoning is a security attack affecting DNS data, not the mechanism for relaying DHCP messages.