yeayu
Enthusiast
Enthusiast

New VLAN added, issues found on guests while detecting the new network config

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Hello all,

I have started facing an odd issue trying to use a new configured VLAN in my vCenter environment...

Basically, my systems "struggle" to identify the new network label (VLAN) configured, leaving the systems disconnected from the LAN.

This condition only disappears when I edit the affected VM, assign a different network label (VLAN), apply the changes and repeat the process by configuring the new VLAN back.

Let's use an example to explain it better:

  • I have a Windows Server/Workstation VM named: VM1
  • I have 2 VLANs configured in vCenter: VLAN50 and VLAN70

VM1 sits on the VLAN50 and has static ip address configured.

I start migrating the machine to a different VLAN, by editing the network settings in the OS (IP, MASK, GW, DNS entries...) and changing the VM1 network label to VLAN70.

At this point, the machine's NIC shows as if it could not connect to anything in the network, although it's configured accordingly to be able to communicate in the new subnet.

I edit the VM again and change the network label to a VLAN different than VLAN70, click OK. Right away I edit the VM settings again to assign back the VLAN70.

After doing so, the OS recognizes successfully the network and starts working as expected...

All my VMs use VMXNET3 adapter and my vCenter version is v5.5 build#2646482

Any idea of what might be going on?

Regards

1 Solution

Accepted Solutions
yeayu
Enthusiast
Enthusiast

We found the issue...

It was not VMware related, but a network misconfiguration: (ESXi connected to two switches, one of them with the VLAN set up correctly and the other one not...).

Thanks for the help provided

View solution in original post

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13 Replies
rcporto
Leadership
Leadership

Sorry for ask, but both VLANs are configured on physical switch (and allowed on the physical ports) where your vSphere ESXi is connected ?

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Richardson Porto
Senior Infrastructure Specialist
LinkedIn: http://linkedin.com/in/richardsonporto
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yeayu
Enthusiast
Enthusiast

Yes, as I described in my initial post, the communication in both VLANs work as expected once the new network is recognized by the VM OS.

The issue here is that it should work the first time I change the VLAN assigned on the VM, no after changing the VLAN back and forth after the OS realizes it is connected to a different subnet.

Regards

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yeayu
Enthusiast
Enthusiast

any ideas?

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rcporto
Leadership
Leadership

Not sure if this is your issue, but how is configured the Notify Switches on Teaming configuration of affected port groups ? See The vSwitch “Notify Switches” setting | Rickard Nobel

---

Richardson Porto
Senior Infrastructure Specialist
LinkedIn: http://linkedin.com/in/richardsonporto
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yeayu
Enthusiast
Enthusiast

Hello again,

I have just checked the Notify switches configuration setting and is enabled.

I have also been reviewing the configuration of that port group in comparison with the others ones working, but I cannot see any difference at all.

I have also tried setting up a different vmnic in a couple of VMs (E1000 instead of VMXNET3), but the issue still occurs.

Any other ideas?

Kind Regards,

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bansne
Enthusiast
Enthusiast

All it need a network refresh.

even if you change ip and then label it might require refresh just to have vm aware n/w configuration is changed. Instaled of changing label from vlan 70 to another then back to 70. You could also try disable and re-enable from OS level. It would work.

greco827
Expert
Expert

Make sure the VM is picking up a port when changing the network port group it is pointed at.  If it is, also go to Networking-->Ports, and do a refresh.

If you find this or any other answer useful please mark the answer as correct or helpful https://communities.vmware.com/people/greco827/blog
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yeayu
Enthusiast
Enthusiast

Thanks, but I am afraid that the network refresh does not work.

Disabling /enabling the network adapter at the OS level does not make any difference...

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bansne
Enthusiast
Enthusiast

do you see any error in event logs? the very moment you change IP and VLAN?

greco827
Expert
Expert

Can you share a screenshot of the VM properties with each of the two network configs, and also one of the vDS ports view with each of the two networks?

If you find this or any other answer useful please mark the answer as correct or helpful https://communities.vmware.com/people/greco827/blog
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yeayu
Enthusiast
Enthusiast

Hi Bansne,

I could not find really useful info in the Event log... apart from some expected warnings when the system is unable to connect to the DNS/ntp servers, as soon as the VLAN is changed.

The curious thing is that if I change to a completely different VLAN by editing the VM and I do it once again selecting the VLAN that was giving me the warnings in the Eventlog, the connection establishes successfully and no warnings/errors are seeing in the EventLogs.

Regards,

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yeayu
Enthusiast
Enthusiast

Hello greco,

Please find it attached.

Just to clarify:

- VLAN 3764 is the one with the odd behaviour

- The rest of listed VLANs work as expected, as soon as the VM is plugged in and its network settings configured.

Regards

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yeayu
Enthusiast
Enthusiast

We found the issue...

It was not VMware related, but a network misconfiguration: (ESXi connected to two switches, one of them with the VLAN set up correctly and the other one not...).

Thanks for the help provided

View solution in original post

0 Kudos