Description

This article explains the reason why vlan interface shows as up/down in SRX firewalls.

Symptoms

The vlan interface shows up/down. This could trigger alerts from Monitoring tools reporting the down status of this interface. 

root@SRX# run show interfaces terse | match vlan

vlan                  up    down

Solution

Junos version 12.3X48 or older: On these versions a VLAN interface is used instead of IRB interface. However, if the VLAN interface is not configured, it is expected for the SRX to show the interface status as up/down. 

Junos version 15.1X49 or newer: On these versions IRB interface is used instead of VLAN interface. However, the vlan interface is still part of Junos software and because it is never configured it will show as up/down.

This behavior is by design and cannot be changed.

If a monitoring tool is alerting about the “down” status of the VLAN, the system will have to be adjusted accordingly.