This is an update to the article from 2009 regarding quieting down snmpd - this time in recent Ubuntu LTS 18.04. The issue at hand is the intense chattyness of snmpd to syslog.

Due to the complete shift to systemd, files in /etc/default are becoming disregarded. Therefore customisations have to be made to /etc/systemd/system. Two steps are neccessary:

Create a symlink for snmpd in /etc/systemd:

ln -s /lib/systemd/system/snmpd.service /etc/systemd/system

Edit that file and change:

ExecStart=/usr/sbin/snmpd -Lsd -Lf /dev/null -u Debian-snmp -g Debian-snmp -I -smux,mteTrigger,mteTriggerConf -f

to

ExecStart=/usr/sbin/snmpd -LS4d -Lf /dev/null -u Debian-snmp -g Debian-snmp -I -smux,mteTrigger,mteTriggerConf -f

Then run

systemctl daemon-reload && service snmpd restart

Now snmpd should be calmed down.

Lately I ran into some issues using snmp tools, e.g.:

snmpwalk -v2c -c public ${host} test

I received errors like:

Unknown Object Identifier (Sub-id not found: (top) -> test)

This is because MIBs are not installed in Ubuntu by default. To install them use the follwing line:

apt-get install snmp-mibs-downloader

Also comment line 4 of /etc/snmp/snmp.conf so it shows:

# mibs:

Hope that helps someone.