If you can't access the SNMP information (enterprise) with snmpwalk or similar or localhost, ie. seeing this:

$ snmpwalk -m MONGO-MIB -v 2c -c mongodb 127.0.0.1:1161 1.3.6.1.4.1.37601
Timeout: No Response from 127.0.0.1:1161

They should verify:

• localhost is in /etc/hosts
• mongod is allowed on 127.0.0.1 in /etc/hosts.allow
• mongod is not blocked in 127.0.0.1 in /etc/hosts.deny
• iptables -nL doesn't show 127.0.0.1 or that port in the loopback interface is blocked
• the agentaddress is correctly set in /etc/snmp/mongod.conf