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FAQ: SNMP Traps and Informs

By Erdem posted 02-01-2016 14:16


SNMP enables users to monitor network devices from a central location. Many network management systems (NMS) are based on SNMP, and support for this protocol is a key feature of most network devices.


Juniper Networks provides many different platforms that support SNMP on Junos OS. Junos OS includes an onboard SNMP agent that provides remote management applications with access to detailed information about the devices on the network.


Junos OS supports:

  • version 1 (SNMPv1)
  • version 2 (SNMPv2c)
  • version 3 (SNMPv3)

SNMP implementation in Junos OS uses a master SNMP agent (known as an SNMP process or snmpd) that resides on the managed device. Various subagents reside on different modules of Junos OS as well (such as the Routing Engine), and these subagents are managed by the snmpd.


The SNMP process opens two additional ports (sockets): one for IPv4 and one for IPv6. This enables the SNMP process to send traps.


SNMP traps on the Junos OS are not compliant with the Alarm Reporting Function (X.733).


For a list of standard SNMP Version1 traps, click Standard SNMP Version 1 Traps.

For a list of standard SNMP Version 2 traps, click Standard SNMP Version 2 Traps.


This article provides answers to the most common questions about SNMP traps and informs.


  1. Does Junos OS impose any rate limiting on SNMP trap generation?
  2. Can I set up filters for traps or informs?
  3. Can I simulate traps on a device?
  4. How do I generate a warm start SNMPv1 trap?
  5. The NMS sees only the MIB OIDs and numbers, but not the names of the SNMP traps. Why?
  6. Can I configure a trap to include the source IP address?
  7. Can I create a custom trap?
  8. Can I disable link up and link down traps on interfaces?
  9. I see the link up traps on logical interfaces, but I do not see the link down traps. Is this normal behavior?