Installed Net-SNMP from OpenBSD binary repository  on my virtual server (VMware) with no problem , I run with SNMP version 1 , test it with snmptrap with no problem , everything is okay.

I did setup device on cacti, the snmp data query well. Bad think happen few minute latter , net-snmp always crash after some periodic time ( trapped by cacti cron ). I did compile from ports with no succcess, the error messege generated from ports is too painfull to debug :/

Recently I try use snmpd came with  OpenBSD  5.7 , did a little configuration , just one line for version 1 on  /etc/snmpd.conf

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Start the snmpd with rc.d script , test it using cacti and  run very stable , no more crash :)