Veeam Data Cloud Vault backup from satellite location

Hi 

recommend you reach out to support. 

What’s actually going wrong

Veeam is failing before the backup even starts.
It’s trying to read some basic VMware files (like the VM’s configuration file), but it can’t properly connect to the ESXi host where the VM lives.

So this is not a VDC Vault problem, and it’s not a storage/Dell SAN problem.
The failure happens inside VMware, between:

Veeam Proxy → ESXi host → datastore

The important bit (very short version)

Your Veeam proxy cannot reach the ESXi host correctly over the network, even though vCenter works.

This almost always comes down to network access or firewall rules at a remote/satellite site.

Common reasons this happens

1. A required port is blocked

Veeam needs a specific VMware port to read VM data.
Very often:

• Port 443 works (so vCenter looks fine)
• Port 902 is blocked (and backups fail like this)

This is extremely common with:

• Site-to-site VPNs
• Firewalls between management networks
• “Locked down” satellite locations

2. The proxy can’t reach the ESXi management network

Even if:

• VMs have network access
• vCenter is reachable

Veeam still needs direct access to the ESXi host management IPs.

If the proxy can’t cleanly reach those IPs, backups will fail.

3. Veeam is using the wrong proxy

Even though you installed a proxy at the satellite site, Veeam may still:

• Pick a proxy from the main site
• Or switch proxies mid-job

That proxy likely can’t reach the ESXi hosts at the satellite site.

4. One ESXi host is more broken than the other

In small 2-node clusters:

• One host often ends up owning the datastore
• Veeam gets redirected to that host
• If that host’s network/firewall is wrong → backup fails

Important clarification about the Veeam Agent

Installing the Veeam Agent inside the VM does not fix this issue.

Why? Because this job is still a VMware backup, and VMware backups must talk to ESXi via the network.

(Agent-based backups only help if you switch to a full agent-only job.)

Things that usually fix it quickly

Try these in order:

1. Check firewall rules
   • From the proxy to every ESXi host
   • Especially port 902
2. Force the job to use only the satellite proxy
   • Don’t let Veeam auto-select proxies
3. Double-check routing
   • Proxy must reach ESXi management IPs
   • No NAT, no weird routing
4. Restart ESXi management services
   • hostd and vpxa on the affected host

If you need a workaround right now

Two reliable options:

Option A – Use agent-based backup

• Create a pure Veeam Agent job
• Send it to the VDC Vault
• Bypasses VMware networking issues entirely

Option B – Put a proxy inside the cluster

• Quick Windows VM
• Add it as a Veeam proxy
• This avoids the problematic network path

Bottom line

Nothing is “wrong” with:

• Veeam itself
• The Dell SAN
• The VDC Vault

This is almost certainly a network access issue between the proxy and ESXi hosts, which is very common at satellite sites.

Great it was a simple fix. 

Great it was that simple and you got it fixed.