Skip to main content
epinheiro
Staff
epinheiro
Staff
October 6, 2025

Technical Tip: HA fails after SNMP configuration on FortiGate 120G/121G

  • October 6, 2025
  • 0 replies
  • 395 views
Description This article describes an HA failure observed on FortiGate 120G/121G devices after enabling SNMP queries.
Scope FortiGate 120G/121G, SNMP, EMAC-VLAN, HA.
Solution

When SNMP queries are enabled on FortiGate 120G/121G devices, the HA cluster may become unsynchronized if SNMP queries target EMAC-VLAN interfaces on npu-vlink (for example, npu-0-1-222, npu-0-1-224, etc.).

 

The problem is triggered when querying the ifSpeed OID for EMAC-VLAN interfaces, such as:

 

snmpget -v2c -c <user> <host> ifSpeed.32

snmpget -v2c -c <user> <host> ifSpeed.45

snmpget -v2c -c <user> <host> ifSpeed.46

snmpget -v2c -c <user> <host> ifSpeed.47

  

After such queries, the FortiGate stops responding to SNMP, and the HA cluster fails. In this condition, both units can assume the master role simultaneously. Recovery requires a power reboot of both devices.

 

  • Affected versions: FortiOS v7.2 and v7.4.

  • Resolved version: FortiOS v7.6.4.

 

Note: Physical interfaces or VLAN interfaces do not exhibit this behavior.
    Terms & ConditionsAccessibility statement