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Windows Server 2012 losing network connection

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Last Modified: 2018-05-22
Hi Guys,

We installed a server well over a year ago and had no problems with it until we recently moved it to a different site.

The Server is a Dell PowerEdge R720, Windows Server 2012 R2 that runs Hyper-v With 2 VMs (Exchange Server and AD/File Server) which i shall refer to as the 'Host'

We use Veeam Backup from another server to backup the two VMs and ever since the move around 2 weeks ago we've only been able to get a solid backup with Veeam 2-3 times.

Upon looking into this a bit further i found that the Host could not be pinged by the Backup server, i then found that i could not access the host through regular RDP either. The only way to access the server was to remote on from one of the VMs.

Once on the server i found that the Host seemed to have no connection to the network and could not ping anything other than the two VMs that it hosts.

The thing that i'm finding a little odd is that the VMs and the entire network are having no issues at all. The only issue coming from this is that the Veeam server can not find the Host meaning that it can't perform the backups.

If the Host is rebooted it seems to fix the problem for a few days and then it will just randomly start happening again.

The server has 4 Network connections configured into a NIC team.

Has anyone experienced anything similar in the past? or can anyone think of anything that may help to resolve this?

Thanks in advanced,
Karl
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John TsioumprisSoftware & Systems Engineer
CERTIFIED EXPERT
Distinguished Expert 2019

Commented:
Possible a blocked port on the firewall ?
ChrisSr. Systems Engineer

Commented:
Bad patch cable? have you tried swapping cables? or bad port on the patch panel.
Stuart SmithTechnical Director

Author

Commented:
I've tried disabling the firewall on the host and still have the same issue.
I'm currently in the process of getting rules set up on the external firewall to ensure that nothing internal is being blocked.

I was thinking that it could be a patch cable too, however it's throwing me off because the VMs, which use the same connections, are having no issues.
Stuart SmithTechnical Director

Author

Commented:
Also - The Connection is NIC Teamed 10GB and all is green and connected correctly  directly to the switch- so not a bad connection /patch lead
ChrisSr. Systems Engineer

Commented:
Are the switch ports configured correctly for the type of teaming you have specified?
For example: your NICs are configured to use LACP, but the ports are only configured for LBFO.
Stuart SmithTechnical Director

Author

Commented:
It's an unmanaged switched so we do not have access to change any of those settings.

However it seems to work for a few days once the server has been rebooted
ChrisSr. Systems Engineer
Commented:
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Stuart SmithTechnical Director

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Commented:
This was performed before noticing the assisted solution
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