ipv6 vs. ipv4

[Kilian Schauer]

17.04.2022 10:20:03 Hendrik Friedel <hendrik at friedels.name>:

> Hello,
> 
> I understood that wireguard prefers ipv6 over ipv4 by default.
> Nevertheless, on both Windows and Android I do not get a connection (only sent bytes no received bytes) when using my domain (friedel.dynv6.net). If I use the IP (2a00:6020:1bfb:c700:ba27:ebff:fe3e:6c55), I get a normal connection.
> I can imagine that WG uses ipv4 (the A-record is set, I cannot change that, but it points to an invalid ip)
> 
> How can I -when using the domain- enforce that ipv6 is really used?
> 
> Apart from that, my suspicion is that ipv4 is in fact used here... How can I really find out, why I get no bytes on the received counter?
> 
> Best regards,
> Hendrik

Hi Hendrik,

the WireGuard mobile apps prefer IPv4 for connecting to the peer, since this helps roaming between networks (where many are still IPv4-only). If the A record of the Endpoint domain is broken, it won't work.
If you want to force an IPv6 transport, you either need to put a raw IPv6 address into Endpoint, or use an AAAA-only domain.

Hope this helps,
Kilian