Cannot see virtual machine using nslookup

[flycast]

I have a Unitrends backup virtual machine running as a virtual machine. I also have a Windows Server running as a virtual machine. I can ping anything on the network from the Windows virtual machine. I can ping the windows virtual machine from physical machines on the network. The issue is when using name lookup on the Unitrends backup machine the Unitrends cannot see the Windows server to back it up.

Our IP addresses are dynamic and I need to use name lookup rather than a hard coded IP address in Unitrends. Unitrends is using nslookup to get IP addresses. When I log in SSH to Unitrends and run nslookup I do not get an IP address for my Windows server by name. I DO have the correct DNS servers configured. Nslookup on the Unitrends does return the correct IP addresses for other machines, just not the other virtual machine.

I have turned off the firewall on the Windows server and on the Unitrends backup server - didn't help.

Not sure what the issue is but feels like a setting in EXSi. Any help troubleshooting this would be appreciated.

[pwilk]

What are the settings on your virtual switches? Do you use distributed switches? Do you have NSX setup in your environment? Is the traffic coming from the physical boxes going through the same equipment as the virtual one? Have you tried different commands such as traceroute on that VM?

Cheers,

Paul Wilk

[Yuva_1990]

Hi

Just to isolate the issue can we try migrating the VM to a different ESXi host (If possible migrate it to the same host where unitrends VM is running ) and run ns lookup if its is failing again we can rule out ESXI host

Regards

Yuvaraj

[flycast]

Good questions. I will do the best I can to answer some of them.

This is a single ESXi environment in stalled on my first server. There is no secondary machine or ESXi environment to migrate to. No NSX. I don't think I have distributed switches. I do have a PC that is connected to the same physical switch that the ESXi machine is on.

At this point it looks like the issue is somehow related to name lookup on the local nameservers. If we use nslookup to get an IP address for either virtual machine the local nameservers don't recognize the name. If we use IP address in nslookup then we get the proper name back.

Edit: I meant to post the image of the ESXi network settings.

[prateekpatalVCP]

it does not seem Esxi network problem, try to add dns entrey on Unitrends  server hosts file.

[flycast]

Won't a DNS entry in the hosts file be the same as creating a static IP? Although the IP may never change this Windows server is a dynamic IP. If I add a hosts entry that will force that host name to a certain IP.

[pwilk]

Try refreshing DNS on both machines (flush DNS/nscd restart). At this point I believe there's nothing wrong with the configuration on the ESXi. It must be something related to either guest OS or the physical network