When using Interface Description Parsing with a SubInterface, the SubInterface will show on the applicable port page. However if an alert is then created to show when this subinterface is down, an alert is never generated. If the description is instead added to the physical interface, the alerts work fine.
The interface description and alert are built in Libre as follows:
Output of ./validate.php
===========================================
Component | Version
--------- | -------
LibreNMS | 26.3.1 (2026-03-17T04:25:34-05:00)
DB Schema | 2026_03_05_112733_ospfv3_instances_nullable (374)
PHP | 8.4.10
Python | 3.12.3
Database | MariaDB 10.11.14-MariaDB-0ubuntu0.24.04.1
RRDTool | 1.7.2
SNMP | 5.9.4.pre2
===========================================
[OK] Composer Version: 2.9.5
[OK] Dependencies up-to-date.
[OK] Database Connected
[OK] Database Schema is current
[OK] SQL Server meets minimum requirements
[OK] lower_case_table_names is enabled
[OK] MySQL engine is optimal
[OK] Database and column collations are correct
[OK] Database schema correct
[OK] MySQL and PHP time match
[OK] Active pollers found
[OK] Dispatcher Service is enabled
[OK] Locks are functional
[OK] Python wrapper cron entry is not present
[OK] Redis is unavailable
[OK] rrd_dir is writable
[FAIL] Some RRD files have the incorrect step. 1/82703
[FIX]:
lnms maintenance:rrd-step all
RRD files with incorrect step:
icmp-perf.rrd: step is 60, should be 300
[OK] rrdtool version ok
[OK] rrd_dir is writable
[FAIL] Some RRD files have the incorrect step. 1/82703
[FIX]:
lnms maintenance:rrd-step all
RRD files with incorrect step:
icmp-perf.rrd: step is 60, should be 300
[OK] rrdtool version ok