Bug ID 1971165: Duplicate NAT IPs leading to client connection failures

Last Modified: Jul 15, 2026

Affected Product(s):
BIG_IP_NEXT(BNK) BNK(all modules)

Fixed In:
2.1.0

Opened: Jun 24, 2025

Severity: 2-Critical

Symptoms

Multiple TMM pods reserve and utilize identical NAT IPs. This can be observed in TMM stats, specifically in the 'fw_nat_reserv_ip_range_stat' table, and in the MRFDB output.

Impact

Duplicate NAT IP reservations can lead to client connection failures. This occurs because the server-side router might route return traffic to the incorrect TMM pod.

Conditions

This issue arises when a TMM pod releases previously reserved NAT IPs and is subsequently deleted. The exact timing of deletion is not significant.

Workaround

Delete the NAT Custom Resource (CR) and recreate it. However, this should not be done within the NAT IP reservation timeout period (default: 15 minutes) following the deletion of a TMM pod.

Fix Information

NAT IPs are no longer duplicated.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips