Re: Bug#1110883: release-notes: mDNS resolution in systemd-resolved disabled by default, breaking existing setups

Richard Lewis <richard.lewis.debian-gM/[email protected]> writes:

> On Tue, 12 Aug 2025 at 15:27, Colin Crawford <[email protected]> wrote:
>>
>> Hi Chris,
>>
>> Thanks for the quick reply. I'm not a developer, so I'm afraid I
>> don't know what an MR is or how to submit a patch. However, I've
>> taken the text of the relevant NEWS item from the systemd-resolved
>> package as a starting point for the text below. Please let me know
>> if this draft is useful:
>>
>> For trixie, mDNS support is now globally disabled by default in systemd-resolved.
>
> can we explain what mDNS is - or link to somewhere that does. i have
> tried and failed to understand what it's purpose is before, without
> success.
>
>> Users relying on mDNS who are not already using Avahi
>
> this bit is a bit confusing as it starts talking about one package and
> then mentions avahi which is a different package. I suggest:
>
>
as usual, i missed out a word, so adding some markup, and guessing what
mDNS is for:



In trixie, **systemd-resolved** no longer enables mDNS support by
default to prevent conflicts with the **avahi** package. mDNS helps you
access systems and devices, such as printers, on your local network.

To continue using systemd-resolved's mDNS support you can run the
following as root:

.. code-block::

        mkdir -p /etc/systemd/resolved.conf.d/
        touch /etc/systemd/resolved.conf.d/00-disable-mdns.conf

It is recommended to do this before upgrading to ensure your system
remains reachable.