TLDR; Is there a way of fixing the "source address" that SNMPD should use?
We are having issues with reply snmpd packets sourcing from the egress
interface and not the loopback interface which the poll request was sent to
We have many GRE tunnels and various routes which traffic can take to and
from our OpenBSD boxes. As such we poll the loopback interfaces instead of
a specific interface, however the snmpwalk replies reply with the source IP
of the egress interface and not the IP which was connected to.
We tried setting "listen on $IP_Lo1" etc, and this seemed to work, but it
is unstable. That is, occasionally packets start being sourced from the
egress interface again when something changes until snmpd is restarted.
Also traps are always sourced from the Egress interface regardless of
"listen on", however our monitoring system only knows about the loopback
interface and so the traps are dropped.