I'm using the snmp modular input app to collect my NAS data to Splunk.
1. I configure the snmp using the poll attributes method
2. I put my MIBs file into SPLUNK_HOME/etc/apps/snmp_ta/bin/mibs/
3. i checked the SNMP port in the NAS side(161) and is working
4. i also checked use this "index=_internal sourcetype=splunkd snmp" result: