Challenge
A Backup or Replication job utilizing Application-Aware Processing fails with the error:
RPC error:The RPC server is unavailable. Code: 1722
Cause
Possible causes include, organized from most common to rarest:
The ports that Veeam Backup & Replication is attempting to use are blocked by a firewall.
Antivirus or Antimalware software may attempt to interact with the VeeamVSSSupport service executable.
The VeeamVSSSupport service is stuck on the Guest OS
Dynamic port allocation needs to be configured.
Solution
Firewall / Ports
A complete list of used ports can be found here: https://helpcenter.veeam.com/docs/backup/vsphere/used_ports.html#ms_servers
When Veeam Backup & Replication connects to a VM, it creates firewall exclusions for the ports and processes it uses. Veeam Backup & Replication, however, cannot add firewall exclusions to hardware or third-party software firewalls.
The Dynamic RPC ports assigned to the temporary guest agents are the most common ports that cause this issue when using Application-Aware Processing.
Dynamic RPC port range: 49152 - 65535
Note: The NIC’s Network Location being set to Public mode will also cause this, as Public mode sets the firewall to its strictest settings.
