[systemd-devel] plans/roadmap for mdns support in resolved

[Lennart Poettering]

On Wed, 19.11.14 15:57, Vasiliy Tolstov (v.tolstov at selfip.ru) wrote:

> > Note that link-local ipv6 addresses for the name resolution stuff
> > aren't fun to use in Linux right now, as the glibc NSS eats up the
> > scopeid, when a client wants to resolve a hostname and specifies an
> > address family. THis has the effect that resolving to link-local IPv6
> > addresses via "ssh" will just work (since ssh makes no restrictions on
> > the address family when resolving the hostname), but via "ping6" will
> > actually fail (since ping6 specifies AF_INET6 as address family...).
> 
> Hm I need very specific use-case. I have eth0, eth1, dummy0 with ipv6
> addresses in different nets and i need to assign hostname to dummy0
> address, that can be reacheable via eth0 or eth1 =).
> Does this possible?

Both LLMNR and mDNS are strictly per-link, they will not announce IP
addresses that are not on the very link that is used for traffic. That
means if you have eth0 then the hostname will be announced with eth0's
set of addersses on it. If you have eth1, then the hostname will be
announced with only eth1's addresses. And similar for dummy0's
addresses, or any other interface's.

Also note that LLMNR/mDNS only works on interfaces that provide
multicasting, i.e. only those which appear in "ip link" with the
MULTICAST flag set.

I am not sure I grok what you are trying to do, but do note that you
can easily add an additional address to any interface you like,
including the same address to multiple links. This means to make
resolved announce a specific address via LLMNR/mDNS is just a matter
of adding it to the interface via "ip addr add".

Lennart

-- 
Lennart Poettering, Red Hat