Some connections seem blocked inside VM

[ram0042]

Hello:

I have a strange issue where I install a plain proxmox server, I install a Windows VM.
I try to install a program that validates a subscription but it claims it doesn't find a valid internet connection (even thought the VM can go browse online).
I did use TCPview on both VM and bare metal PC separate on the same network. TCPview shows some 443 ports being used on the bare metals along with 80.
On the VMs it shows only 80.
I disabled all firewalls even in Windows Firewall. I have no clue where to check next.

 

[ram0042]

So far I've noticed it happens with Windows Server images. I use the appropriate NetKVM driver from the virtio package. I tried 2022 and 2025 with same result. Windows 11 on proxmox works just fine with its drivers. I tried Windows 11 drivers for Server 2025 and no change.