This article provides a step-by-step procedure for replacing a faulty SRX managed by Mist with a new RMA replacement.

Prerequisites:

1. Zeroize the new device that will replace any SRX.
2. Ensure that the device can reach the internet or can ping 8.8.8.8. Please maintain this internet link until the whole process is complete.
3. Keep the new device onboarded (unassigned) on the MIST platform. Please refer to Link for the steps to adopt SRX.
4. Mist will automatically upgrade the replacement to the same Junos version as the other node.
5. Additional notes if this is a cluster node replacement:
   1. Before you begin, if you have preempt configured on the redundancy groups, deactivate those lines with additional CLI commands.
      From the remote shell:
      mist@node1> show configuration | display set | match preempt
      set chassis cluster redundancy-group 1 preempt
      set chassis cluster redundancy-group 1 preempt
      set chassis cluster redundancy-group 1 preempt
      
      In this example, we have preempt on three redundancy groups. So we will add the following to the additional CLI commands at the bottom.
      deactivate chassis cluster redundancy-group 1 preempt
      deactivate chassis cluster redundancy-group 2 preempt
      deactivate chassis cluster redundancy-group 3 preempt
   2. Save, and sync the configuration.
   3. After the replacement is complete and the new SRX has rejoined the cluster in a healthy state, remove the above additional CLI commands, then save and re-sync.

The new SRX is onboarded as unassigned on the MIST platform, follow these steps to replace the SRX:

1. Go to Organization > Inventory > WAN Edges > Select the Site from the UI.
2. Click on the SRX.
3. Once the WAN Edge Page is available, select Utilities > Replace WAN Edge.

4. Choose the SRX shown in the Replace window that you want to replace.

5. The MAC address of the unassigned SRX will be available in the drop-down list.

           6. Once the process is complete and the device is online, connect all the cables to this device and put it in place of the faulty Node. In case of a cluster, you will need to power off "request system power-off" or halt the                     device using the command " request system halt " before connecting all the cables, else there will be a "Split-Brain" scenario causing network problems.

Note that in case of a standalone device, if the device being replaced (faulty device) is still online, it will still have the configuration after the process is completed.
Please consider that, due to this, you will have 2 different devices with the same config and that could create problems in the network.

Additional cluster notes:

• This process will take about 30 minutes to an hour.
• Make sure the replacement device is the exact same hardware.
• Mist will automatically upgrade the replacement to the same Junos version as the other node.
• Mist will then set the node to clustering and reboot it.
• The new node will come online and then inherit the configuration from the existing node.
• After the replacement is complete and the new node has joined the cluster in a healthy state, an additional re-sync of the Mist configuration is suggested. If you have already done this to re-enable preempt, this is not necessary.

2024-05-12 : Article Created

2025-07-08 : Added additional notes for cluster node replacement

2025-07-21 : Clarified "similar" Junos version for upgrade/downgrade.