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FAQs - High-availability

Answers to the most frequently asked questions covering licensing, Flexi port modules, features, and hardware support.

Which licenses do I need when I have two devices in high-availability mode?

For active-active mode:

  • Each device requires its own subscriptions, and the active subscriptions must match on both devices.
  • Zero-day protection doesn't affect the HA setup regardless of the expiry date on each device.

For active-passive mode:

  • Only the active device requires a license subscription. Sophos Firewall ensures the passive device has a copy of those subscriptions, so it can take on processing if the active device fails.

    It's therefore vital that the subscriptions are activated on the intended active device. You must ensure that HA is turned on only from the device which has a valid subscription.

  • If a software or virtual device is used, you need to purchase only one base license, and once that serial number is registered, Sophos Firewall will manage the creation of the passive device. There's no need to purchase a separate base firewall license for the passive device or a separate serial number.

  • The firewall that carries the license subscription must be configured as the primary node in the HA initial setup.


Active–Passive mode isn’t available for Sophos Firewall in Azure.


When configuring physical devices in active-passive mode, you need a license activated on the passive node to configure the network interfaces. You can use the trial license for this. If the trial license has already been used, for example, if the device has been reset, you must contact customer care to obtain a new trial license.

Is the synchronized application control feature supported in active-active mode?


Is it possible to establish an HA pair between XG 210 and an SG 210?

No. XG 210 can only connect to another XG 210 in HA. An XG 230 or even an SG 210 can't be used.

What happens if I manually synchronize the HA?

If you manually synchronize any of the HA cluster devices, the firewall drops all the masqueraded connections.

What happens if I restore a backup without HA configuration after enabling HA?

If a backup without HA configuration is restored after configuring HA, then HA is disabled. The primary device is accessible according to the backup configuration. The auxiliary device is accessible with the auxiliary admin IP address.

How do I RMA a firewall that's part of an HA cluster and using Sophos Central Synchronized Security?

You must remove the cluster from Sophos Central management before returning the device as part of the RMA process.

When you receive the new firewall, you must re-register the new HA cluster in Sophos Central. This process will remove conflicts with the license and serial number synchronization if the old device is still registered in Sophos Central.