Bug ID 759878: BPDUs forwarded by STP passthru mode are not seen by tcpdump

Last Modified: Jun 19, 2025

Affected Product(s):
BIG-IP TMOS(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, 15.1.4, 15.1.4.1, 15.1.5, 15.1.5.1, 15.1.6, 15.1.6.1, 15.1.7, 15.1.8, 15.1.8.1, 15.1.8.2, 15.1.9, 15.1.9.1, 15.1.10, 15.1.10.2, 15.1.10.3, 15.1.10.4, 15.1.10.5, 15.1.10.6

Opened: Feb 27, 2019

Severity: 4-Minor

Symptoms

When STP is in passthru mode (the default setting), the layer-2 forwarding logic for STP BPDU packets occurs entirely within the broadcom switch. As a result, egressing STP BPDU packets will not be seen in a tcpdump capture (even if capturing on the interface). The ingress BPDU packets will be captured as normal.

Impact

STP BPDU frames seen arriving at other devices may not appear in an egress capture on the BIG-IP device, despite having been sent by the BIG-IP device.

Conditions

STP is in passthru mode Platform other than (C117, C115, C112, C113)

Workaround

Take tcpdump on the device which connect to BIG-IP egress interface to verify whether STP is passthrough.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips