JunOS : Alarm Management Ethernet Link Down

By | October 24, 2016

Having the red alarm led on but nothing is wrong with your JunOS powered Juniper device?

First, look out what alarm is triggered by issuing the following command :

If absolutely nothing is really wrong, you will see the following alarm :

Alarm time Class Description
2016-01-20 07:11:59 UTC Major Management Ethernet Link Down

The alarm above is triggered if the out-of-band management port on the back (for EX series switch for example) or the MGMT ethernet port on the MX serie routers isn’t connected. If you know what you are doing and use in-band management, you can “safely” disregard this error and tell your device to ignore it using the following command :

NOTE : Best practice speaking, I would recommended to use an out-of-band network in addition to the in-band management. Additionally, if you really want to have the peace of mind, I would also connect the device to a serial server appliance! (especially if you are managing transit provider devices) it might save you one day!