Bug ID 1758957: If two tenants share the same VLAN, TMM may egress broadcast traffic even when VLANs are disabled in F5OS

Last Modified: Mar 07, 2025

Affected Product(s):
BIG-IP F5OS, F5OS-A, F5OS-C, Velos(all modules)

Known Affected Versions:
17.1.1, 17.1.1.1, 17.1.1.2, 17.1.1.3, 17.1.1.4, 17.1.2, 17.1.2.1, 17.5.0

Opened: Dec 05, 2024

Severity: 2-Critical

Symptoms

In certain scenarios, such as restoring a UCS on an F5OS tenant, if the VLANs in F5OS are disabled, the TMM may egress broadcast traffic such as gratuitous ARPs onto the disabled VLANs.

Impact

This could cause IP address conflicts on the network or other issues related to unexpected broadcast traffic such as gratuitous ARPs on the network.

Conditions

-- VLAN is currently assigned to any tenant. -- An F5OS tenant where VLANs were assigned and then removed. -- An F5OS tenant where TMM is not in forced-offline mode. -- An action occurs on the tenant (such as restoring a UCS or restarting TMM, or loading the config) that results in gratuitous ARPs.

Workaround

- In F5OS, remove the affected VLANs from the LAG or interface. - In F5OS, ensure there is at least one VLAN still attached to the tenant. This could be a temporary VLAN. - On the tenant, use forced offline to prevent traffic egress. - If you are restoring a UCS from another BIG-IP such as for a platform migration, put the source BIG-IP into a forcedoffline state before taking the UCS. - Delete the tenant, and recreate without any VLANs assigned. - In F5OS, remove the VLAN from all tenants.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips