[SOLVED] Host IPv4, Guest IPv6 subnet (guest no connectivity) Debian 11 bullseye


New Member
Sep 24, 2022
Dear people,
I have been struggling on the following issue for about 2 days now, and figured I should take a break and ask for some advice on the forums.
Furthermore, a note, I'm not super familiar to the networking part of IT, so that might be why this is not working out for me. (I have followed multiple guides)

General information infrastructure: (please correct me if anything here is wrong).
I am running a dedicated server running Proxmox on Debian 11 bullseye ⇾ it is installed on my NVMe with no issues
I'm setting up a routed config as I have a single IPv4, but do have a IPv6 subnet 2a01:4f8:***:***::/64.
Routed setup: because then I could assign my VM's their own IPv6 IP connected from HOST IPv6 connectivity, so no IPv4, as my hosting told me I would not need to order additional MAC addresses and/ or IPv4's. (already had abuse reports when trying bridge , as then no extra MAC addresses are allowed)​
  • Networking Host (Proxmox)
    • IPv4 for main connectivity
    • IPv6 for getting connectivity on my VM's (but also works on Host when I test: "wget -O - v6.ident.me 2>/dev/null && echo")
      • Config at /etc/network/interfaces:1664018057821.png
      • Sysctl config:
  • Networking Guest (test VM running Debian 11)
    • IPv6 for connectivity as I do not have additional IPv4's and even though I would, I still like to use IPv6.
      • Config at /etc/network/interfaces:
General issue Infrastructure:
Seems to me that there are no issues.​
  • Service:

  • Connectivity test:

  • Connectivity test externally:

    So seems to be no issues on HOST
  • Service:
  • Connectivity test:

    • VM doesn't have nslookup or wget as limited install because no internet access.
  • Connectivity test externally:
    From Windows computer located in Belgium while dedicated root is in Germany.
    So, my IPv6 assigned is reachable from outside, but from inside to outside it does not reach networks.
    When I restart the machine, it becomes unreachable from Windows computer, until it boots, and becomes reachable again.
Any suggestions would be greatly appreciated!


  • 1664018686504.png
    5.6 KB · Views: 7
Just added a new VM (Windows Server 2022), and did not change anything in my network config at Proxmox.
Added vmbr0 as network device (Model Intel E1000, not same as on Linux VM)

and inserted following config in IPv6 on adapter:

Can resolve google at IPv6 level, of course websites without IPv6 I won't be able to resolve...
So fixed this by using a DNS64 provider, in particular: http://www.trex.fi/2011/dns64.html

So, I'm doing something wrong in the network config on the Linux virtual machine...
Any suggestions?
Last edited:
Quick update!
I was able to resolve the issue myself by finding out it was an issue regarding the use of correct DNS/ nameservers.
The reason I wasn't able to access the internet at the fullest is because I didn't have DNS64 nameservers equipped.
https://nat64.net/ says it all!
When using one of their public nameservers for IPv6 to IPv4 translation, everything has been resolved.


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