Monitor interface status with SNMP and Nagios
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I've noticed that SNMP on pfSense isn't well documented and most articles have you running down rabbit holes chasing down MIBs or some other nonsense. So, I wanted to post my findings and let others chime in if I missed anything.
My goal was to monitor the operational status of an interface using Nagios. Here's what I did:
List MIBs using snmpwalk: [nagios@nagios etc]$ snmpwalk -v 2c -c CommunityString 10.10.1.1 ^ ^ Protocol version Read Community STRING pfSense uses 2c This is set in pfSense You will get a lot of output but you mainly want these: IF-MIB::ifDescr.2 = STRING: em1 IF-MIB::ifDescr.12 = STRING: pppoe1 IF-MIB::ifDescr.13 = STRING: wan_stf IF-MIB::ifDescr.14 = STRING: ovpns2 S2S IF-MIB::ifDescr.15 = STRING: ovpns3 RAS IF-MIB::ifDescr.16 = STRING: ovpnc1 Proton IF-MIB::ifOperStatus.2 = INTEGER: up(1) IF-MIB::ifOperStatus.12 = INTEGER: dormant(5) IF-MIB::ifOperStatus.13 = INTEGER: dormant(5) IF-MIB::ifOperStatus.14 = INTEGER: up(1) IF-MIB::ifOperStatus.15 = INTEGER: up(1) IF-MIB::ifOperStatus.16 = INTEGER: down(2) Find the OID (add arg -O n): [nagios@nagios etc]$ snmpwalk -v 2c -O n -c CommunityString 10.10.1.1 IF-MIB::ifOperStatus .1.3.6.1.2.1.2.2.1.8.1 = INTEGER: up(1) .1.3.6.1.2.1.2.2.1.8.2 = INTEGER: up(1) .1.3.6.1.2.1.2.2.1.8.3 = INTEGER: down(2) .1.3.6.1.2.1.2.2.1.8.4 = INTEGER: down(2) .1.3.6.1.2.1.2.2.1.8.5 = INTEGER: down(2) .1.3.6.1.2.1.2.2.1.8.6 = INTEGER: dormant(5) .1.3.6.1.2.1.2.2.1.8.7 = INTEGER: up(1) .1.3.6.1.2.1.2.2.1.8.8 = INTEGER: up(1) .1.3.6.1.2.1.2.2.1.8.9 = INTEGER: up(1) .1.3.6.1.2.1.2.2.1.8.10 = INTEGER: up(1) .1.3.6.1.2.1.2.2.1.8.11 = INTEGER: up(1) .1.3.6.1.2.1.2.2.1.8.12 = INTEGER: dormant(5) .1.3.6.1.2.1.2.2.1.8.13 = INTEGER: dormant(5) .1.3.6.1.2.1.2.2.1.8.14 = INTEGER: up(1) .1.3.6.1.2.1.2.2.1.8.15 = INTEGER: up(1) .1.3.6.1.2.1.2.2.1.8.16 = INTEGER: down(2) ^---------------------^ | OIDs Display Status of OID/MIB: MIB: nagios@nagios etc]$ snmpwalk -v 2c -c CommunityString 10.10.1.1 IF-MIB::ifOperStatus.2 IF-MIB::ifOperStatus.2 = INTEGER: up(1) OID: [nagios@nagios etc]$ snmpwalk -v 2c -O n -c MIMIR-Technologies 172.177.1.1 .1.3.6.1.2.1.2.2.1.8.2 .1.3.6.1.2.1.2.2.1.8.2 = INTEGER: up(1) Nagios service: The (-R [1345]) is regex for anything but 2, which is a down status) define service{ use generic-service,srv-pnp host_name pfsense service_description Interface: Outside [wan_stf] check_command check_snmp!-C CommunityString -o .1.3.6.1.2.1.2.2.1.8.13 -R "[1345]" } -
Thanks, very useful :)
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Have you done anything with the SNMP modules in the latest pfSense?
Just curious, and thanks for your post!SNMP modules
MibII
Netgraph
PF
Host Resources
UCD
Regex -
If you're interested, I did a write-up and released code for various pfSense non-SMTP checks with Nagios -- CPU, memory, pfSense services, VPN/IPSEC tunnels, interfaces, state table, firmware version, CPU temperature, system uptime, and more. The checks work on both Nagios Core and Nagios XI.
https://www.linuxincluded.com/monitoring-pfsense-with-nagios-xi-using-ssh-part-1/