Ubuntu install snmpd

# apt-get install snmp snmpd

# vi /etc/snmp/snmpd.conf

#  Listen for connections from the local system only
#agentAddress  udp:127.0.0.1:161
#  Listen for connections on all interfaces (both IPv4 *and* IPv6)
agentAddress udp:161,udp6:[::1]:161

# /etc/init.d/snmpd restart

References :
How To Install and Configure an SNMP Daemon and Client on Ubuntu 14.04 | DigitalOcean