Bug ID 475584: Packets might be silently dropped if there is no ARP entry for the nexthop

Last Modified: Apr 10, 2019

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(all modules)

Known Affected Versions:
11.0.0, 11.1.0, 11.2.0, 11.2.1, 11.3.0, 11.4.0, 11.4.1, 11.5.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.5.4, 11.5.4 HF1, 11.5.4 HF2, 11.5.4 HF3, 11.5.4 HF4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8, 11.6.1, 11.6.1 HF1, 11.6.1 HF2, 11.6.2, 11.6.2 HF1, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 11.6.4

Fixed In:
12.0.0

Opened: Aug 14, 2014
Severity: 3-Major
Related AskF5 Article:
K17003

Symptoms

Ingress packet count differs from egress packet count.

Impact

Packets may be silently dropped if there is no ARP entry for the nexthop. No counters show dropped packets. ICMP Error Destination Unreachable is sent. Diagnosis as to reason for lost packets is difficult or impossible.

Conditions

This is for IPv4 with a static route. No MAC address for the next hop and ARP request is delayed or times out. This can happen with an early burst of traffic and a delayed ARP reply.

Workaround

Create a static ARP entry for the neighbor/gateway Use a monitor

Fix Information

There is now a counter that reports discarded packets that are dropped due to neighbor queue overflow.

Behavior Change