Le 20/12/2023 à 14:30, Belanger, Martin a écrit :
Hi,
On one of my servers, I use avahi to realize mDNS resolution. With avahi I am
able to choose on which ip version I want avahi to answer to mdns requests
(ipv4 or ipv6). In my opinion, this is convenient on local networks with both
stacks, espacially for tracking purposes on the network).
This is indeed convenient, however according to RFC 6762, paragraph 6.2 [1]:
When a Multicast DNS responder sends a Multicast DNS response message
containing its own address records, it MUST include all addresses
that are valid on the interface on which it is sending the message,
I interpret this as MUST include both IPv4 and IPv6 addresses (i.e. per
standard the IP family should not be configurable). One way to solve this
would be to disable IPv4 (or IPv6) on an interface so that the interface only
has IPv4 or IPv6 addresses assigned to it.
[1] https://datatracker.ietf.org/doc/html/rfc6762#section-6.2
I have understood that avahi has to be replaced by systemd-networkd and/or
systemd-resolved and I have tried to implement the save behavior with it...
Without success (may be I have not found the correct place to adjust it).
Following are the capabilities I would like to find in systemd for mDNS resolution
(espacially on a server) :
- One can specify If he wants systemd to respond only in ipv4 or ipv6 (or both,
by default ?) ;
- In ipv4, one can specify the sub-network on which he wants systemd to
respond to mdns requests (in my opinion, the full ipv4 adresse is to be
elaborated by systemd-network) ;
- in ipv6, one can specify the prefix on which he wants systemd to respond to
mdns requests (in my opinion, the full ipv6 adresse is to be elaborated by
systemd-network) ;
Thank you in advance for reading me.
Regards.
Jean-Marie Delapierre
I agree with your answer , but ...
- The goal of mDNS is to resolve adresses only on a local network , not
the internet . On the internet , one has to respect the standards , but
, on his own local network , it can admited that he does what he wants .
- The goal of any software is not only to respect a standard . It also
has to allow the users to do what they want to do . As much as I
understand that the default behavior of systemd HAS to be the full
respect of the standard , as much it has to allow fine tuning for the
user to do what he wants on his private local network . For example ,
look on all the options you have to configure your local ethernet
network . Most people don't use them and are happy with the default
configuration , but some ...
so, I suggest systemd-resolved to propose two options for mDNS resolution :
- in ipv4 : none (ipv4 answering is disabled as if the interface would
have no ipv4 adress) , all (default) , a list of ipv4 subnetworks
(answering the adress on each subnetwork if avalaible) .
- in ipv6 : none (ipv6 answering is disabled as if the interface would
have no ipv6 adress) , all (default) , a list of ipv6 prefixes
(answering the adress on each prefix if avalaible) .
Thank you in advance for reading me.
Regards.
Jean-Marie Delapierre
