VMs on same host cannot communicate

[hypercat]

I have 2 VMs on the same host machine running ESXi 5.1. One VM is running Windows 2008 R2 Standard and the other is Windows 2008 Standard. This configuration has been up and running for quite some time without (as far as I knew) any issues. However, today I went to push out some Windows updates to one of the VMs from the other (which is the WSUS server) and saw an error message indicating that it was unable to communicate with the WSUS server.  Investigating further, I found that neither of these two machines cannot communicate with the other.  They have no problems browsing, pinging, etc., the rest of the network but cannot browse or ping each other. They are, as I said, on the same host and the same virtual switch, and they are the only VMs on this host.  There are no visible event log or NIC errors on the machines themselves, although I cannot successfully enable Network and File Sharing on either server. Both servers have static IP addresses, File and Printer sharing turned on, and the Windows fiewall is off.

I'd appreciate any information or ideas on this. I've done my research on the Windows OS and networking end and can't find anything that might cause this behavior so far.

[bspagna89]

Hi,

Are both VMs on the same network? If so can you verify that each VM has the correct VLAN configuration by right clicking each VM -> edit settings -> Network adapter -> correct label for each VM.

Also, can you verify that each VM has its default gateway configured properly. I know you said Windows firewall is off.. Can you validate that each profile that the NIC could be using (Domain, piublic, home etc) is turned off and not just the service itself?

Can you also verify that each server has the correct DNS settings?

That should cover some basics..

[Sateesh_vCloud]

First thing to check Windows firewall service

Next --> Uncheck the Network Adapater and check it from edit settings (Connected option)

Reset the TCP/IP Stack with   nesth winsock reset

[hypercat]

Yes, both VMs are on the same network. Both VMs can browse the Internet and the rest of the network, so the default gateway is correct. There are about 65 other servers, workstations, printers and other devices on the network.  Both VMs can ping other devices on the network by NetBIOS name and FQDN, and one of the problem VMs is the primary DNS server for the network, so no DNS issues. BTW, 5 of the other servers and one workstation are on another VMWare host and these VMs have no problem communicating with any of those VMs. The Windows firewall service is running, but the firewall is turned off for all profiles via group policy (and I checked both machines to make sure they show that this policy has been applied).