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Werk #22191: Network interfaces: service details reveal index, description and alias

Component Checks & agents
Title Network interfaces: service details reveal index, description and alias
Date Aug 20, 2026
Level Trivial Change
Class New Feature
Compatibility Compatible - no manual interaction needed
Checkmk versions & editions
3.0.0b1
Not yet released
Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

The summary of a network interface service shows a single bare value in brackets, for example [tun0]. That value can come from the interface's index, description (ifDescr), alias (ifAlias) or name (ifName), and until now there was no way to tell which one it was — nor whether the device populates the other fields at all. Deciding whether the discovery ruleset Network interfaces and switch ports should switch the option Appearance of network interface from Use index to Use description or Use alias therefore required an SNMP walk or guesswork.

The details of every interface service now spell this out:

Index: 3
Description: tun0
Alias: not set
Service item based on: description (ifDescr)

Index, Description and Alias are always listed, with not set where the device leaves a field empty, so it is visible which fields the device actually fills. Name is added when the device reports ifName. The Service item based on line states which field the service item was derived from; it is missing for services that were discovered before that information was recorded, and for interface groups, whose accumulated attributes carry no per-device naming.

The service summary is unchanged, and so is $SERVICEOUTPUT$ in notifications. $LONGSERVICEOUTPUT$ now carries the block above in place of the bracketed value that was previously repeated there.

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