- Is this SRX3600 in a chassis cluster?
- Are you using fxp0 IP or some other revenue port IP to poll from SNMP server?
If it is a revenue port, then check if interface has SNMP as host-inbound-service using ">show interface <interface-name> extensive" command
- Use "> monitor traffic interface <interface name> no-resolve" command to see if packets are reaching the SRX.
- Was any recent change made to configuration? (like adding/modifying firewall filter on loopback interface)
- Apply SNMP traceoptions using below:
# set snmp traceoptions file snmp-trace
# set snmp traceoptions flag all
# commit
Now generate SNMP packets from your server and see if SRX is receiving them and if yes then what it does with those packets. (>show log snmp-trace)
Regards,
Srinath