You may want to double check that nothing in /etc/default/snmpd is over-riding your configuration. I think by default, the local loopback address (127.0.0.1) is passed in the SNMPDOPTS directive.
I could be mistaken, I just remember having to change that the last time I installed it for Cacti on a Debian system, but I think that was the prior version.
Best Answer
Comment out the lines that start with
com2sec
,group
, andaccess
in snmpd.conf, e.g: