46065: Acronis Backup Advanced: Configuring Communication between Components Placed behind NAT

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Applies to: 

Use FQDN to specify components residing in a remote network (with NAT enabled).

This article applies to:

  • Acronis Backup Advanced (Acronis Backup & Recovery Advanced)


  1. You install Storage Node, Management Agents or another Acronis Backup Advanced components in a remote network.
  2. In this remote network NAT and port forwarding are configured to forward external traffic on port 9876 to the machine with components installed.
  3. You register Storage Node (which reside in a remote network) on the Management Server using external IP of the remote network and want to create a backup plan to a managed vault on this Storage Node. When choosing location for the backup, you receive this error:
    The vault you have selected in unavailable at the moment. Select another vault.
  4. Or you want to register agents (which reside in a remote network) on the Management Server and get this error:
    Failed to establish connection. Check the specified machine address.


The component placed behind NAT redirects requests coming from an external IP because it detects that the external IP does not belong to it.


On the Management server, register the centralized components (License Server, Storage Node) placed behind NAT with their fully qualified domain name. In this case requests between components will come via their hostnames instead of the IPs.

On the managed machine behind NAT check that the centralized components (Management Server, License Server, Storage Node) are available for ping via machine name (FQDN) and the correct IP address is resolved.

If this is not the case, edit the hosts file on the machine and add the corresponding string:
E.g. your AMS_behind_NAT has IP: XX.XX.XX.XX and FQDN: AMS_behind_NAT.mydomain.com

  1. Open C:\Windows\System32\drivers\etc\hosts (/etc/hosts on a Linux machine)
  2. Add this string: XX.XX.XX.XX     AMS_behind_NAT.mydomain.com

Make sure the managed machine behind NAT is reachable via machine name. If not, edit the hosts file on the AMS machine in the same way.

Then add the remote machine by its name.

More information

Please contact Acronis Customer Central if you need assistance.