The following registry setting will enable Veeam Backup & Replication to collect IP addresses from all NICs on the Microsoft Hyper-V server(s) or Off-host backup proxy.
Key Location: HKLM\SOFTWARE\Veeam\Veeam Backup and Replication\
Value Name: HvCollectAllHostAddresses
Value Type: DWORD
Value Data: 1
Rescan the Hyper-V Hosts after the registry value is created on the Veeam Backup & Replication server to update the configuration database.