On Tuesday, September 29, 2020 1:01:23 AM MST Lennart Poettering wrote:
On Mo, 28.09.20 23:37, John M. Harris Jr (johnmh(a)splentity.com)
wrote:
> > Configure "." as "routing domain" on a specific iface and
the lookups
> > wil go there preferably. If you put that on your VPN iface this means
> > DNS traffic goes there preferably. If you put that ont he main iface
> > this
> > means DNS traffic goes there preferably.
>
>
>
> Is that a NetworkManager setting or a systemd-resolved setting? Is that
> going to be exposed in the GUI, or is it something that gets hidden
> away?
I am not an NM guy, but I think they expose this these days. I can
tell you definitely though that this is easily accessible via
"resolvectl domain <iface>" from the command line and from .network
networkd configuration files.
> How does systemd-resolved figure out what domains "should" be sent to a
> given connection's DNS server without some arcane incantation from the
> systemd docs?
As mentioned elsewhere:
1) Search domains are implicitly routing domains: if an interface has
"redhat.com" as search domain we also use that as routing domain,
i.e. all *.redhat.com lookups will go to this interface and not to
others.
2) If neither search domains nor routing domains are configured on any
interface for a domain, lookups are routed to all interfaces in
parallel, and the first positive and last negative answer is used.
i.e. focus is primarily on "let's make DNS work" and "let's make
the
best of the little information we traditionally have", and any
further, more complex routing requires additional configuration in NM,
networkd or directly with resolvectl commands.
Lennart
Lennart,
Search domains have absolutely nothing to do with routing. Search domains are
specifically used for resolving non-FQDN to FQDN. This isn't a reliable way to
see what domains are handled by a VPN, or by any DNS server.
The Red Hat VPN is a good example of this, as not every internal subdomain is
in search domains. That's the case for many VPNs, corporate or personal.
--
John M. Harris, Jr.