VMware VM backups failed post uprgading to VBR 13

[AnubhavSh]

Most of the VM backups failing the day we have upgraded to VBR v13, required port communication is enabled however backups could not run which were running without any errors earlier witg VBR v12.
Also, there are 7 out of 12 proxies which are affected post upgrade, are there any changes happened for TLS communication or FIPS protocol or any additional ports to be opened.
Somehow if I used backup server as a backup proxy for 2 VMware clusters, the backups are happening fine but can't use backup server for each of these clusters.

Error:
Error: read: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond [system:10060]
Getting VM info from vSphere
Error: read: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond [system:10060]

I haven checking with the support on the Case # 08095755, but no luck on this issue. Did anyone encounter this issue or if why is this behavior with VBR v13?

[PatrikSE]

I have the same issue. We have three sites running vSphere, protected thru the same master VBR server. After upgrading from Veeam B&R 12 to 13, all backups for all sites fails. Same error message as you have, is presented for every VM. Meanwhile, all replication jobs keep running successfully.

I attempted to setup a test backup job and lock the backup proxy to the VBR server itself and then the backup succeeds over nbd. (The regular proxies runs either Hot Add mode or SAN mode, depending on site.) Forceing a virtual proxy to use nbd doesn't help.

I also have a support case running Case #08099646

[PatrikSE]

What I found is that if we reverse the traffic initialization by enabling the setting "Run server on this side" for the proxy servers, the backup runs successfully. Network team can still not see any blocks in the network and the Windows firewall on the VBR server and Windows based proxy neither registers any blocks. But wanted to share this temporary fix to get the backups running until Veeam Support gets back.

[AnubhavSh]

Hi, Hope your issue is resolved. I found that traffic over TCP 6162 was getting blocked on the network firewall from the proxy to the repository and in same cases it was blocked for same port from the backup server itself to the backup proxy. Seems like issue it changed in VBR v13 how the Veeam Backup proxy manage backup traffic as TCP 6162 basically for Veeam Data Transport service which is responsible to initiate the Veeam Agent processes on respective servers (Backup proxy, Backup repository, etc).
I could see in the logs, it is using TLS 1.3 now for all backup infrastructure communication, probably that is the cause as the port 6162 was enabled long back and suddenly it stopped which didnt understand well.

[PatrikSE]

Thanks, I forgot to reply here but yes, our issue was fixed too and it was indeed network issues with the firewall blocking traffic. After the network team confirmed that no traffic was blocked in any direction and temporary allowed any-any traffic in the firewall we had to rule out firewall issues. But as they digged further they discovered that TCP 6162 was blocked from proxy to backup server anyway. After opening that port in the firewall the backups worked again without the "Run server on this side" setting.