The Ubuntu SNMP client worked correctly with SHA authentication, but failed with MD5.
Error: Authentication failure (incorrect password, community or key)
snmpd.conf:
sysServices 72
master agentx
agentaddress udp:161
view systemonly include .1.3.6.1.2.1
rocommunity password default -V systemonly
createuser user MD5 v3_authphrase
rouser v3_authphrase authNoPriv -V systemonly
The command executed to receive data from the client is as follows:
snmpwalk -u user -l authnopriv -a MD5 -A v3_authphrase localhost