Last Modified: Mar 24, 2026
Affected Product(s):
F5OS F5OS-A, F5OS-C
Known Affected Versions:
F5OS-A 1.8.0, F5OS-A 1.8.1, F5OS-A 1.8.2, F5OS-A 1.8.3, F5OS-C 1.8.0, F5OS-C 1.8.1, F5OS-C 1.8.2
Opened: Dec 10, 2025 Severity: 2-Critical
L2/FDB entries may expire even when traffic is arriving at the FPGA of the Appliance or VELOS Blade.
The expiration of the FDB entry can lead to Destination Lookup Failures that are rate-limited, i.e. traffic loss. Depending on the scenario this could lead to intermittent potential outages between the entry expires, and it is learnt again.
L2 entries which internally hash to the same table index inside the FPGA can lead to the expiration of the entry when traffic is arriving on intervals of more than 30 seconds from that MAC address. On each interval, an age refresh message might be lost, leading to decrement the age of the entry on 30 seconds. When the entry reaches the last period it will expire, and then it will be re-learnt again.
Create a static FDB entry for the MAC address that suffers expiration issues. See K000152328. Ensure that traffic from the MAC address expiring arrives continuously under 30 seconds intervals. Open a Support case and request an EHF.
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