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.
These ports are:
- 1025 to 5000 (for Microsoft Windows 2003)
- 49152 to 65535 (for Microsoft Windows 2008 and newer)
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.