My Hyper-V VMs don't see VLAN-tagged networks.
On the host the physical NIC or virtual switch must be on a trunk, and on the VM NIC you set the right VLAN ID. Forgetting one of the two is the most common mistake.
Try this first
- 1Check the physical switch port: trunk mode with the correct VLANs allowed. No native/untagged VLAN if it would cause confusion.
- 2On the Hyper-V host: New-VMSwitch -SwitchType External, bound to the correct physical NIC. No VLAN config at vSwitch level, that lives per VM.
- 3On the VM NIC: Set-VMNetworkAdapterVlan -VMName 'vm' -VMNetworkAdapterName 'NIC' -Access -VlanId 20.
- 4Test: inside the VM run ipconfig, ping the default gateway of VLAN 20. If it fails check Get-NetAdapter and Get-VMNetworkAdapterVlan.
- 5For the management OS in a VLAN: Set-VMNetworkAdapterVlan on the management OS adapter. Careful: misconfigured and you lose admin access.
When to bring us in
For cluster hosts or SCVMM, configure Logical Networks and VM networks consistently on every host. Otherwise migrations fail when a VM moves from host A to a host B that lacks the SCVMM vNet.
See also
- One DC or two DCs for an SMB office?Two is almost always the right answer; one DC is a single point of failure for logon, DNS and GPOs.
- Should I split FSMO roles across two DCs?For a small domain all on one DC is fine; with two DCs splitting is tidier but not required.
- How do I know my AD replication is healthy?Replication errors creep in silently; they only surface when logins or GPOs misbehave.
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