Template:FAQ:Agent 28

The most likely explanation is that the new version of the agent is looking in a different location than the previous one. This is commonly experienced when replacing a ready-installed version (e.g. from a vendor distribution), with the current release installed from the source.

The default location for this file with the basic distribution is /usr/local/share/snmp/snmpd.conf (or PREFIX/share/snmp/snmpd.conf). Ready-installed versions often look for the file as /etc/snmpd.conf, or /etc/snmp/snmpd.conf. Try moving the old config file to the new location, and restart the agent.

With release 5.0, the name of the package changed from "ucd-snmp" to "net-snmp", and this change was reflected in the name of the persistent /var directory. So a v5 Net-SNMP agent will not look in /var/ucd-snmp/snmpd.conf for settings from a v4 UCD agent.