Challenge
Backup network traffic does not use the NICs associated with IPs configured within the preferred network rules for a Microsoft Hyper-V Host.
Cause
This can occur because, by default, Veeam Backup & Replication stores only the IP addresses for Hyper-V hosts that DNS provides.
Solution
To configure Veeam Backup & Replication to collect the IP addresses of all NICs on the Microsoft Hyper-V server(s), create the following registry value on the Veeam Backup Server:
Key Location: HKLM\SOFTWARE\Veeam\Veeam Backup and Replication\Value Name: HvCollectAllHostAddressesValue Type: DWORD (32-Bit) ValueValue Data: 1
After this registry value is created on the Veeam Backup Server, rescan the Hyper-V Hosts to update the recorded IP addresses for the rescanned host.
