Does anyone know if it is possible to backup a Hyper-v 2008 R2 cluster that resides in a different domain than the domain that the Veeam Backup server resides in? I am not sure if my isssue is a firewall issue or a cross-domain issue. The situation is as follows. Our Veeam server is in our internal network on an internal domain. The Hyper-v cluster is on a separate domain on a separate network. We have allowed ports through the firewall for the VMM and Hyper-v hosts to communicate to the Veeam backup server based on the Hyper-v User guide (22, 135, 137-139, 445, 2500-5000, 6160-6190, 8100).
I was able to create a Veeam Backup job pointing to the VMM Server and I was able to add all vm's to the backup job. When I try to perform a backup on any of the vm's, I get the following error on each vm backup: "Task failed Error: The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)".
Instead of trying to add the vmm server to the job, just for testing purposes, I tried to add a single hyper-v host to the job and went through the backup wizard for a standalone Hyper-v server. Here is the error message I got this time "Unable to connect via WMI. Hostname: [testserver] Server 'testserver.xx.lcl' does not exists or access denied. Check firewall settings. The RPC server is unavailable. (Exception from HRESULT: 0x800706BA). So I wasn't even able to create a job when trying to create a standalone backup job whereas I was able to create a job when pointing to the vmm host and was able to enumerate the vm's. I have tried to create the jobs with both the local administrator account of the vmm and hyper-v hosts and with a admin domain account in the hyper-v domain.
I then ran wbemtest from the Veeam backup server and tried connecting to the hyper-v host \\testserver.xx.lcl\root\cimv2, and I get the same error as when I try to add the standalone hyper-v server to a job "Number: 0x800706ba Facility: Win32 Description: The RPC server is unavailable.
I am now thinking that the veeam backup job requires wmi and that wmi can't query machines across domains. Anyhow, I know that I can just install a Veeam backup server or vm in each network and be done with it, but am still curious what is causing these issues. One other thing. The windows firewall has been turned off on the hyper-v hosts and the vmm server.