BIG-IP system incorrectly forwards VLAN-tagged frames with STP at Pass Through mode

ID F5:K39604784
Type f5
Reporter f5
Modified 2019-12-20T22:40:00


F5 Product Development has assigned ID 758527 to this issue. F5 has confirmed that this issue exists in the products listed in the Applies to (see versions) box, located in the upper-right corner of this article. For information about releases, point releases, or hotfixes that resolve this issue, refer to the following table.

Type of fix | Fixes introduced in | Related articles
Release | 15.1.0
12.1.5 | K2200: Most recent versions of F5 software
Point release/hotfix | | K9502: BIG-IP hotfix and point release matrix


To work around this issue, you can disable global STP. To do so, perform the following procedure:

Impact of workaround: STP is enabled by default on all BIG-IP interfaces to help prevent bridge loops. F5 recommends testing any changes in an appropriate environment.

  1. Log in to the TMOS Shell (tmsh) by entering the following command:


  1. To disable global STP, use the following command syntax:

modify /net stp-globals mode disabled

  1. Save the configuration by entering the following command:

save /sys config