[systemd-devel] Regression in ipv6 resolutions in systemd-resolved with AF_UNSPEC

[Lennart Poettering]

On Fri, 19.02.16 15:43, Sébastien Luttringer (seblu at seblu.net) wrote:

> Hello,
> 
> Since systemd v229, I have one server which no more resolve ipv6 adresses when
> it use nss-resolve and AF_UNSPEC.
> 
> This issue seems to be linked with the DNS resolver used on its network. This
> resolved is provided by a french FAI box (SFR).
> 
> I'm currently not able to understand precisely where is the issue, but opening
> the socket with AF_UNSPEC does not resolve ipv6 and with AF_INET6
> does.

Note that resolved will not look up IPv6 addresses if this isn't
explicitly requested if there are no local routable IPv6 addresses
configured. And vice versa, it won't look for IPv4 addresses if this
isn't explicitly requested and there are no local routable Ipv4
addresses configured. Basically, when doing lookups without specifying
what you want, we'll return something that you can actually talk
to. If during resolving you however specify what you want, then we'll
actually return that.

How precisely does your IP configuration look like? Do you use
per-interface DNS servers (i.e. configured via networkd), or do you
have global DNS servers configured via /etc/resolv.conf or via DNS= in
/etc/systemd/resolved.conf?

If you use per-interface DNS servers, do you have a routable IPv6
address on that interface? If you use global DNS servers instead, do
you have any routable Ipv6 address on any interface?

Lennart

-- 
Lennart Poettering, Red Hat