Fortinet not responding to MIB

1st is snmp enable on the interface and you have the correct  snmp-community or user/auth if v3?

Did you run "diag debug application snmpd -1 "

e.g 

  diag debug enable

  diag debug reset

  diag debug app snmpd -1

If your calling up mib buy name, I would stop and do a simple snmpget or snmpwalk against the device? Does it reply?

e.g 

  snmpwalk -c bahblah -v2c x.x.x.x

  or a simple sysname get

  snmpget -c blahbahb;ah -v2c x.x.x.x   .1.3.6.1.2.1.1.5.0

Ken Felix