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Network backup / Restoring a configuration

How to restore a configuration from backup

What to check first, when to restore everything and when to apply just one section, and the commands for MikroTik, Juniper, Huawei VRP and OLTs.

Updated
Audience
Network teams
Reading time
8 min

01Before restoring

  1. Pick the version. Compare the backup with the current configuration (or with the previous version) and confirm it is the one you want. See Comparing configuration versions.
  2. Check the software version. A configuration from a very different version may contain commands that no longer exist or changed syntax. That is why it pays to keep the version with every backup.
  3. Make sure you have out-of-band access. Serial console, separate management network or someone on site. A bad restore can take down your own remote access.
  4. Agree on the window. A full restore interrupts service; warn support and the affected customers.
  5. Save the current state. Back up what is on the device now, even if it is wrong. It is your way back.

02Restore everything or just one section

SituationDo this
Device replaced, reset or with its configuration lostFull restore
Someone deleted or changed one part (rule, VLAN, ONU, BGP session)Apply only that section, copied from the backup
A planned change went wrongUndo only what the change touched; the diff shows exactly what

In a partial restore, the commands in the text backup are the same ones you would type in the terminal. Copy the block, review it and paste it into a configuration session.

03MikroTik RouterOS

Full restore from the export (.rsc), on a reset or new device: upload the file and run

/system reset-configuration no-defaults=yes run-after-reset=backup.rsc

From the binary backup, on the same router:

/system backup load name=backup.backup

Partial: copy the lines from the export and paste them into the terminal. On RouterOS 7, make sure the export was made with show-sensitive; without it, PPPoE passwords and keys are not in the file. More in Automatic MikroTik backup.

04Juniper Junos

configure
load override /var/tmp/backup.conf
show | compare
commit confirmed 5

commit confirmed rolls back on its own if you do not confirm within 5 minutes. To restore just one section, use the configuration in set format (show configuration | display set) and apply it with load set terminal. More in Juniper Junos backup.

05Huawei VRP

For a full restore, copy the file to the device storage (over SFTP or FTP), set it as the startup configuration and reboot:

startup saved-configuration backup.cfg
display startup
reboot

display startup confirms which file will be loaded before the reboot. For sections, paste the backup commands in system-view.

06OLTs (Huawei, ZTE, VSOL, Datacom)

On OLTs, the most common case is not restoring everything but recovering deleted ONUs or profiles. To do that:

  1. compare the backup from before the problem with the current configuration and pick out the lines that disappeared;
  2. reapply the profiles first (line, service, traffic), then the ONUs, then the service-ports or VLANs;
  3. test one ONU before applying the rest;
  4. save the configuration (save on Huawei, write on ZTE).

A full OLT restore from a file varies by model and software version. Follow the vendor procedure for your version and use the text backup as a reference to check the result.

07After restoring

  1. Confirm the service: BGP sessions, PPPoE authentication, ONUs online, traffic.
  2. Save the configuration on the device, if the system requires it.
  3. Take a fresh backup right away and compare it with the restored version: the difference should be only what you expected.
  4. Write down what happened and what was reapplied.