Bug ID 907765: BIG-IP system does not respond to ARP requests if it has a route to the source IP address

Last Modified: Nov 07, 2022

Bug Tracker

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

Known Affected Versions:
15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3, 15.1.0.4, 15.1.0.5, 15.1.1, 15.1.2, 15.1.2.1, 15.1.3, 15.1.3.1, 16.0.0, 16.0.0.1, 16.0.1, 16.0.1.1, 16.0.1.2

Fixed In:
16.1.0, 15.1.4

Opened: May 08, 2020
Severity: 2-Critical

Symptoms

If the BIG-IP system receives an ARP request from a source IP address for which it has a route configured via another interface, the BIG-IP system does not send an ARP reply.

Impact

The BIG-IP system does not send an ARP reply.

Conditions

-- BIG-IP system receives an ARP who-is request for one of its self ip addresses. -- The source IP address is in a different network, and the BIG-IP system has an L3 route configured for it via a different interface from where the ARP request was received

Workaround

None.

Fix Information

A db variable has been added called 'arp.verifyreturnroute' that can disable the TMM process's checking for a valid return route for ARP requests. It defaults to 'enable', which is the normal BIG-IP behavior. It can be set to 'disable' to disable the dropping of the request if a return route exists.

Behavior Change

A db variable has been added called 'arp.verifyreturnroute' that can disable the TMM process's checking for a valid return route for ARP requests. It defaults to 'enable', which is the normal BIG-IP behavior. It can be set to 'disable' to disable the dropping of the request if a return route exists.