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FAQ: Junos OS Dual Routing Engine Configuration and SNMP

By Erdem posted 02-02-2016 11:03


SNMP enables you 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)

The SNMP configuration should be identical between the Routing Engines when configuring for continued communication. However, we recommend having separate Routing Engine IDs configured for each Routing Engine, when using SNMPv3.


By default, SNMP is disabled on a Juniper Networks device. To enable and configure SNMP, click Configuring SNMP on devices running Junos OS.


To ramp up on SNMP implementation in Junos OS, click Understanding SNMP implementation in Junos OS.


This article provides answers to the most common questions dual Routing Engine configuration and SNMP.


  1. In my system, the MIB object snmpEngineBoots is not in sync between two Routing Engines in a dual Routing Engine device. Is this normal behavior?
  2. Is there a way to identify that an address belongs to RE0, RE1, or the master Routing Engine management interface (fxp0) by looking at an SNMP walk?
  3. What is the best way to determine if the current IP address belongs to fxp0 or a Routing Engine, from a CLI session?
  4. When there is a failover, the master hostname is changed since the hostname belongs to the Routing Engine. Is this correct?