Port 445, or SMB, is used to transfer the guest processing runtime/components from VBR to the SQL-Server. Take a look at this page from the helpcenter: 

https://helpcenter.veeam.com/docs/backup/vsphere/used_ports.html?ver=120#ms-sql-guest-os-connections

@regnor Thanks for your reply, But in the Firewall, I saw that the system SQL Server to Veeam Server uses Port 445, please advise.

DMNSOD-CM-12 = SQL Server
DMNSOD-VB-12 = Veeam Server v.12

Hyper-V server 2022

Those drops only appear while the backup is running? 

What kind of backup job have you configured and what are you using as a target backup repository?

@regnor 
1. Those drops only appear while the backup is running?

   (A) Yes, detected by the PA Firewall.

2.What kind of backup job have you configured and what are you using as a target backup repository?

(A) Hyper-V VM guest backup and Veeam Server Local disk repository.

Unfortunately I don’t have an idea why the guest VM would connect to the VBR server via SMB. Maybe you can find any hints in the Veeam Guest Processing Logs on the SQL server itself; %PROGRAMDATA%\Veeam\Backup

If not, I would suggest to open a case and let support check your configuration.

Hi @Kwok Eddie -

Were you able to contact Support as “regnor” suggested to ge a resolution for your question? If so, could you share what they did and post it, then make what you share they did as ‘Best Answer’ so others may benefit from your post if they experience the same issue?

Thank you.