A network administrator is configuring firewall security rules between a Layer 3 router acting as a DHCP relay agent and a centralized DHCP server located at . Workstations on a remote host VLAN generate broadcast DHCP lease requests that the router receives, but the relay agent fails to deliver the unicast requests to the DHCP server because firewall policies block the traffic. Which transport protocol and destination port combination must be permitted on the firewall for the relay agent to successfully forward client requests to the DHCP server?
- UDP port 67Answer
- BUDP port 68
- CTCP port 67
- DTCP port 68
Answer
UDP port 67 must be allowed on the firewall to permit communication from the relay agent to the DHCP server.
DHCP servers receive incoming messages from both direct broadcast clients and unicast DHCP relay agents on UDP port 67. Allowing UDP port 67 on the intermediate firewall enables the relay agent to successfully forward the encapsulated request packets to the centralized server.
Step-by-Step Solution
Key Concept
DHCP Relay Transport Protocol and Port Assignment