Failed to process replication – Port 2501

Recently, I had a global replication error for one of my customer with Veeam Backup & Replication v9. We are seeing the following error which is causing replicas to fail: “Failed to process replication task Error: Failed to connect to the port [HYPER-V-HOST-2501]“. Came across this error recently which is thankfully an easy fix but there is not a lot out there, the following is the error and the fix.


Replication error: “Failed to process replication task Error: Failed to connect to the port [HYPER-V-HOST-2501]


When you perform backup and replication jobs in the Hyper-V environment, VM data is processed directly on the source Hyper-V host where VMs reside, and then moved to the target, bypassing the backup server.VM data processing can produce unwanted overhead on the production Hyper-V host and impact performance of VMs running on this host. To take data processing off the production Hyper-V host, you can use the off-host backup mode.

The off-host mode shifts the backup and replication load to a dedicated machine — an off-host backup proxy. The off-host backup proxy functions as a “data mover” which retrieves VM data from the source datastore, processes it and transfers to the destination. So in both of these cases, there is a target proxy and a source proxy involved. The error is not indicating an issue with the B&R server communicating with the proxy, it is indicating the failure of the target proxy to make its connection back to the source proxy to retrieve the data so you should focus on the proxy-to-proxy portion of the connection. In replication workflow, Hyper-V proxy has to be able resolving DNS name of every target devices (Hyper-V cluster target and nodes).


First, choose a backup mode for the replication. Edit your Backup Proxy and select “Off-host backup” button, then “Failover to on-host backup mode if no suitable off-host proxies available” and “Use the following backup proxy servers only:” options. Enable your Hyper-V nodes needed to use as proxy servers.

Basically, you have to edit your DNS configuration to allow the communication (name resolution and IP address) between source Hyper-V proxy servers and target Hyper-V proxy servers. Also, you have to add DNS settings manually into source Hyper-V proxy servers by editing Host File in Windows directory of source proxy servers: C:\Windows\System32\drivers\etc 😉


Hyper-V upgrade from Windows 2012 R2 to 2016: Guide.

If you need to disable UAC Server on Windows Server 2016 Script Guide.

Need to deploy Veeam Agent for Windows Follow this guide!

Need to deploy Veeam B&R 9.5 Update 2 Follow this guide!

You can learn more about Veeam Backup & Replication v10 here.


Please follow and like us:

1 ping

  1. […] Continue reading » […]

Leave a Reply


Enjoy this blog? Please spread the word :)