LLMNR [1] is multicast name resolution protocol. I think it should be
disabled on all Server deployments unless explicitly requested by the
administrator. Unfortunately it breaks some kinds of DNS queries [2]
because the way it is implemented in systemd-resolved. It makes dig -t
NS org. return error telling that domain does not exist.
I think LLMNR should be disabled in whole distribution, because even
Microsoft is removing support for it [3]. I doubt it were wanted even in
Server builds especially. Those usually rely on more controlled
infrastructure, meaning standard unicast DNS.
If you would know a common use case, why it should be still wanted, can
you share it? I have created issue #114 for it on fedora-server [4].
Have you ever used single label name to connect to your server? I think
mDNS has less problematic implementation in avahi, but that has to be
enabled explicitly. I think that is desired especially on servers.
It were introduced by systemd-resolved change [5], but there were no
statement that it would have negative impact on DNS resolution.
What would you think about it?
1.
https://www.rfc-editor.org/rfc/rfc4795
2.
https://bugzilla.redhat.com/show_bug.cgi?id=2220973
3.
https://techcommunity.microsoft.com/t5/networking-blog/aligning-on-mdns-r...
4.
https://pagure.io/fedora-server/issue/114
5.
https://fedoraproject.org/wiki/Changes/systemd-resolved#Local_multicast_DNS
--
Petr Menšík
Software Engineer, RHEL
Red Hat,
https://www.redhat.com/
PGP: DFCF908DB7C87E8E529925BC4931CA5B6C9FC5CB