Host Discovery Failures in Veeam x vCenter

For the port do you mean 443 not 442 right?  If VBR cannot communicate to vCenter it can throw this message and can be a variety of things like network, traffic, being busy, etc.  It is one that is a “it depends” answer unfortunately.  If you edit the vCenter in VBR and go through the wizard that tends to fix it.

Hello Chris,

Yes, the port is 443. I’ve tried using the wizard, and it works only at that time but fails most of the time. On 10 Host discovery job only 2 successes, remaining fails

Here are the repeated errors I found in the debug logs at:

C:\ProgramData\Veeam\Backup\Utils\Util.VolumesHostDiscover.log

[17.11.2024 03:07:21.918]    <17>   Error (3)    Failed to resolve IPs of omni.cube.io
[17.11.2024 03:07:21.918]    <17>   Error (3)    Failed to resolve name: omni.cube.io. Error: This is usually a temporary error during hostname resolution and means that the local server did not receive a response from an authoritative server.  (Veeam.Backup.Common.CCppComponentException)
[17.11.2024 03:07:21.918]    <17>   Error (3)    Agent failed to process method {Network.ResolveHostName}. (Veeam.Backup.Common.CCppComponentException)

Hi ​@sangeetha -

Is your DNS records set up ok?

This is what I would check next is DNS as Shane points out.  If you cannot resolve IP > Hostname and vice versa you will need to look at the hosts file.

​@coolsport00 , ​@Chris.Childerhose - DNS records are OK

Well ​@sangeetha ...there appears to be some connection issue between your VBR server and vCenter. Firewall, ports, network, Windows UAC are all things to look for here. Do you have individual ESXi Hosts added or just vCenter? You don’t need individual Hosts if you add vCenter.

So you can ping the IP and get a DNS FQDN back and vice versa?  If one or the other does not work then it is not working properly.

The way I read it, Veeam does not fail when adding vCenter, but during host discovery.

The Veeam VBR server not only needs to talk to the vCenter, it also needs to talk to the ESXi servers. The host discovery runs directly against the ESXi hosts, not via the VC.
Therefore, for the connection 
vCenter --> ESXi(s) port 443,902 (TCP) is required

For clarification, here is the port list

Ports - User Guide for VMware vSphere

As ​@Chris.Childerhose and ​@coolsport00 described, all componentes should be reachable through DNS (forward and reverse!)

Glad to hear you were able to resolve the issue.

Glad you ended up figuring it out ​@sangeetha 👍🏻