Comment 10 for bug 1812748

This may have nothing to do with netplan indeed, and I think it's a duplicate of https://bugs.launchpad.net/ubuntu/+source/net-snmp/+bug/1246347

A while back I came up with these reproduction steps:

- install snmpd
- install snmp-mibs-downloader
- add a nic alias. With ifconfig I did:
ifconfig eth0:1 10.0.100.209 netmask 255.255.255.0

- restart snmpd
- journalctl -u snmpd --follow

Wait a bit. The error should show up every 30s.