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Werk #19972: Fortigate interface check: expose ifName via 'name' attribute, restore ifAlias

Component Checks & agents
Title Fortigate interface check: expose ifName via 'name' attribute, restore ifAlias
Date May 13, 2026
Level Prominent Change
Class Bug Fix
Compatibility Incompatible - Manual interaction might be required
Checkmk versions & editions
3.0.0b1
Not yet released
Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

The Fortigate interface check previously substituted ifName for ifAlias in its SNMP wire layout: the value of OID .31.1.1.1.1 (ifName, the technical name like port1.5) was placed into the alias attribute, while the actual ifAlias OID was not fetched at all. The "Use alias" item-appearance option therefore returned the technical name on Fortigate hosts but a user-defined string on every other device — a long-standing inconsistency rooted in the fact that name did not exist as a first-class interface attribute. (History: werks 4539 → 6638 → 11267.)

With werk #19971, the shared if64 parser fetches ifName and populates a dedicated name attribute. The Fortigate-specific hijack is no longer needed and is removed: ifAlias is now fetched and exposed at the alias attribute like on every other SNMP device, and the technical interface name is available via the name attribute.

Incompatible change

If you currently use the option Appearance of network interface = Use alias on Fortigate hosts (the historical default for technical interface names), discovered services will keep the existing item names on the next service rediscovery only if you switch the rule to Use name first.

Migration

  1. In the discovery ruleset Network interfaces and switch ports, open the rules that apply to your Fortigate hosts.
  2. Change Appearance of network interface from Use alias to Use name.
  3. Rediscover services on the affected hosts and accept changed services.

If you rediscover without changing the rule, items will be derived from the actual ifAlias (often empty on Fortigate), and Checkmk will fall back to the interface index.

To the list of all Werks