Monitoring Juniper SRX240 with MRTG

Quick MRTG config to get number of current sessions on a Juniper SRX Cluster

WorkDir: /var/www/mrtg-srx-sessions
EnableIPv6: no
WorkDir: /var/www/mrtg-srx-sessions
Options[_]: gauge,growright,nopercent,avgpeak

PageTop[_]: SRX240Sessions
YLegend[_]: SRX240 Sessions in Use
ShortLegend[_]: Sessions
LegendI[_]: node0
LegendO[_]: node1
MaxBytes[_]: 1000000000
AbsMax[_]: 1000000000
Title[srx240-sessions]: SRX240 Cluster active sessions
Target[srx240-sessions]: .1.3.6.1.4.1.2636.3.39.1.12.1.1.1.6.0&.1.3.6.1.4.1.2636.3.39.1.12.1.1.1.6.10:public@192.168.1.1

You can work out the OID from the juniper

aland@fw> show snmp mib walk decimal .1.3.6.1.4.1.2636.3.39.1.12.1.1.1 
jnxJsSPUMonitoringFPCIndex.0 = 0
jnxJsSPUMonitoringFPCIndex.10 = 0
jnxJsSPUMonitoringSPUIndex.0 = 0
jnxJsSPUMonitoringSPUIndex.10 = 0
jnxJsSPUMonitoringCPUUsage.0 = 28
jnxJsSPUMonitoringCPUUsage.10 = 1
jnxJsSPUMonitoringMemoryUsage.0 = 64
jnxJsSPUMonitoringMemoryUsage.10 = 63
jnxJsSPUMonitoringCurrentFlowSession.0 = 15520
jnxJsSPUMonitoringCurrentFlowSession.10 = 16830
jnxJsSPUMonitoringMaxFlowSession.0 = 131072
jnxJsSPUMonitoringMaxFlowSession.10 = 131072
jnxJsSPUMonitoringCurrentCPSession.0 = 0
jnxJsSPUMonitoringCurrentCPSession.10 = 0
jnxJsSPUMonitoringMaxCPSession.0 = 0
jnxJsSPUMonitoringMaxCPSession.10 = 0
jnxJsSPUMonitoringNodeIndex.0 = 0
jnxJsSPUMonitoringNodeIndex.10 = 1
jnxJsSPUMonitoringNodeDescr.0 = node0
jnxJsSPUMonitoringNodeDescr.10 = node1

And snmpwalk them from Linux

snmpwalk -v2c -c public 192.168.1.1 .1.3.6.1.4.1.2636.3.39. 
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.6.0 = Gauge32: 14194
1.12.1.1.1.6
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.6.0 = Gauge32: 13441
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.6.10 = Gauge32: 15323
1.12.1.1.1
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.2.0 = Gauge32: 0
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.2.10 = Gauge32: 0
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.3.0 = Gauge32: 0
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.3.10 = Gauge32: 0
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.4.0 = Gauge32: 29
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.4.10 = Gauge32: 0
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.5.0 = Gauge32: 64
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.5.10 = Gauge32: 63
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.6.0 = Gauge32: 13796
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.6.10 = Gauge32: 14757
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.7.0 = Gauge32: 131072
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.7.10 = Gauge32: 131072
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.8.0 = Gauge32: 0
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.8.10 = Gauge32: 0
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.9.0 = Gauge32: 0
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.9.10 = Gauge32: 0
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.10.0 = Gauge32: 0
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.10.10 = Gauge32: 1
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.11.0 = STRING: "node0"
iso.3.6.1.4.1.2636.3.39.1.12.1.1.1.11.10 = STRING: "node1"