Bug ID 676491: BIG-IP as a DHCP relay while in a DHCP relay chain will use its self-IP as the relay agent.

Last Modified: Sep 06, 2019

Bug Tracker

Affected Product:  See more info
BIG-IP LTM, PEM(all modules)

Known Affected Versions:
12.1.0, 12.1.0 HF1, 12.1.0 HF2, 12.1.1, 12.1.1 HF1, 12.1.1 HF2, 12.1.2, 12.1.2 HF1, 12.1.2 HF2, 12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5, 12.1.3.6, 12.1.3.7, 12.1.4, 12.1.4.1, 12.1.5, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.1, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 13.1.3, 14.0.0, 14.0.0.1, 14.0.0.2, 14.0.0.3, 14.0.0.4, 14.0.0.5, 14.0.1, 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.4, 14.1.0.5, 14.1.0.6, 14.1.2, 15.0.0, 15.0.1

Opened: Aug 01, 2017
Severity: 2-Critical

Symptoms

DHCP request is relayed to backend DHCP servers with Self-IP as relay agent instead of DHCP Virtual IP in case of Relay Chaining. DHCP server will not be able to use the giaddr field to make a subnet determination while providing an IP address to a client.

Impact

In a DHCP relay chain, BIG-IP does not relay agent right before the pool of DHCP servers.

Conditions

DHCP relay chain, BIG-IP should be the relay agent right before the pool of DHCP servers.

Workaround

1. The relay chain should be used across a single subnet if the DHCP server uses the giaddr to determine subnets for the clients. 2. If the use case is to load balance across multiple DHCP servers and the 3rd part DHCP relay cannot do so, LTM load balancing can be used.

Fix Information

None

Behavior Change