Veeam Port Usage

[RH_BK]

Hello,

I have an odd behaviour with Veeam B&R. The Backup for our 2 onprem Exchange Servers suddenly stopped working a few days ago.
There were no changes made to the Backup, the Exchange Servers nor the Firewall.

Code: Select all

Failed to inventory guest system: Veeam Guest Agent is not started  

Failed to prepare guest for hot backup. Error: Failed to check whether snapshot is in progress (network mode). RPC function call failed. Function name: [IsSnapshotInProgress].  Target machine: [Exchange-IP]. RPC error:The RPC server is unavailable.  Code: 1722  

After some debugging I noticed that there are several blocked packets in the firewall logs.
So I opened all Ports from B&R Server to both Exchange Servers for testing -> Backup was succesful
After that successful try I closed the previous opened ports -> 1st Exchange backups still successful, 2nd Exchange shows the previous error again.

So I went back in debugging the Firewall, the blocked Port was TCP/16901, nothing else.
I opened the Port, next try and next blocked Port comes up, now it is TCP/7065.
Also opened that port, next try, now TCP/6601 is blocked.

None of this ports are mentioned in the Veeam Knowledgebase as a necessary Port
https://helpcenter.veeam.com/docs/backu ... ml?ver=120
https://helpcenter.veeam.com/docs/backu ... ml?ver=120

Before I open a ticket, is there anything I'm missing? It seems completly random which port is used and also why is one Exchange Server backed up successfully and the not?

Best regards
Rouven

[Mildur]

Hi RH_BK

Are those source ports or target ports? I researched the ports with Google:
Port 6601: Microsoft Threat Management Gateway SSTP
Port 7065: unassigned
Port 16901: unassigned

Those ports are not known to me in connection to our products. I also cannot find them in our internal documentation.
Dynamic port ranges used by Veeam Backup & Replication are RPC (49152 to 65535) and Veeam Data Mover (2500 to 3300).

I recommend to open a support case and let them check the logs.

Best,
Fabian

[RH_BK]

Hi Fabian,

these are target ports Veeam tries to connect to on the Exchange Server.
I'll open a support case tomorrow if there won't be any helping comment in this thread.

Thank you.

Best regards,
Rouven