Windows Server 2022 not receiving inbound IPv6 traffic

[Digymkus]

I have Proxmox setup with a single network card and software bridge. The physical network the host is connected to provides IPv4 via DHCP and IPv6 via SLAAC.

I can create VMs with VirtIO NICs and the firewall option disabled, install Linux and everything works (the VM gets IPv4 and IPv6 addresses, can send and receive traffic over IPv4 and IPv6).

However, installing Windows Server Core 2022 (with the VirtIO drivers and guest agent) results in the VM not accepting any traffic over IPv6, even if it can reach out to other systems over IPv6 (I can ping google.com and the IPv6 addresses are used). Enabling remote desktop and response to ping only allows IPv4 traffic in.

It's been a while since I tried, but I don't remember having any issues when running the same Windows Server Core 2022 as a VM on the same OS as a Hyper-V host.

Has anyone else encountered the same issue?

 

[kakuni]

The problem should be with Windows, since it is working fine with the Linux VM.
By default, firewall in Windows Server is configured very strictly.
Have you checked the setting?

 

[Digymkus]

I would have thought allowing remote management and ping from the main menu (using Server Core install) would enable it for both IPv4 and IPv6. Is that not so?

 

[cwt]

You can enable ICMP for v6 via PS:

netsh advfirewall firewall add rule name="ICMP Allow incoming V6 echo request" protocol="icmpv6:8,any" dir=in action=allow