Fedora 33 Planning To Enable Systemd-Resolved By Default

[intelfx]

Afaik it's a drop-in replacement as it's taking the DNS/domain list from /etc/resolv.conf, which is the standard way used by NetworkManager and others (also by systemd-networkd) to interact with current DNS daemons.

https://wiki.archlinux.org/index.php/Systemd-resolved#Automatically

Yes and no.

systemd-resolved taking the list of nameservers from pre-existing resolv.conf is not a recommended mode of operation. In this case you get all the downsides and almost no benefits because resolved is then constrained by the limitations of resolv.conf syntax (and getting around those limitations is what drove the development of resolved in the first place).

[intelfx]

Will this break setting DNS servers through GNOME Settings?

or can NetworkManager tell systemd-resolved of the DNS servers to use.

Of course no. NM explicitly supports resolved.

[intelfx]

I had to disable systemd-resolved because it won't consistently resolve DNS over OpenVPN connections.

It’s quite the inverse. systemd-resolved (when paired with an intelligent enough network tool, e. g. NetworkManager) is the only Linux software in existence that will do the right thing by default when you have multiple interfaces each with its own internal DNS.

[bachchain]

https://github.com/systemd/systemd/i...temd-resolved+ gives me 152 open issues... Wish this number were lesser by the time of F33 release

Around a third of those are feature requests

[loinad]

systemd-resolved supports using your own DNS server(s), and can be configured to not cache anything if you so wish. The problem may be that systemd-resolved supports so many options that one can easily get overwhelmed in all the choices you might want to make (and I seem to recall there were some combinations of options that were technically legal, but almost certainly were not what you really wanted).

So, the solution in an Ubuntu/NetworkManager/systemd-resolved environment to let me specify my own desired DNS server *only* for IPs from the OpenVPN network is...?

[loinad]

So it has been resolve(d).

No, it hasn't. OpenDNS name resolution is totally broken by default on Ubuntu 19.10 for my corporate VPN. The "solutions" presented in this thread either don't work or work temporarily and unreliably for some minutes or until the next reboot: https://askubuntu.com/questions/1032...ted-to-openvpn

Of course the old and expected behavior of editing resolv.conf and adding a nameserver at the top could fix it (if systemd-resolved didn't auto-manage it), but systemd guys couldn't restrain themselves in order not to break the simple and sane behavior of true and tested Linux tools.

[starshipeleven]

https://github.com/systemd/systemd/i...temd-resolved+ gives me 152 open issues... Wish this number were lesser by the time of F33 release

I wish people would actually go and do something useful instead of wishing stuff on a forum.

[q2dg]

https://github.com/systemd/systemd/i...temd-resolved+ gives me 152 open issues... Wish this number were lesser by the time of F33 release

[starshipeleven]

It looks like on this proposal, they're going to make /etc/resolv.conf link to the stub-resolver, so anything reading /etc/resolv.conf talks to resolved instead, which then has its own configuration.

As said in both the Fedora proposal and Arch wiki, NetworkManager will detect this and go change this daemon config.

Something similar is done already by netconfig scripts in OpenSUSE, my /etc/resolv.conf is a dummy symlinked to another file handled or updated by netconfig scripts (integrated with NetworkManager too) called whenever the system feels like it.

cat /etc/resolv.conf
### /etc/resolv.conf is a symlink to /var/run/netconfig/resolv.conf
### autogenerated by netconfig!
#
# Before you change this file manually, consider to define the
# static DNS configuration using the following variables in the
# /etc/sysconfig/network/config file:
#     NETCONFIG_DNS_STATIC_SEARCHLIST
#     NETCONFIG_DNS_STATIC_SERVERS
#     NETCONFIG_DNS_FORWARDER
# or disable DNS configuration updates via netconfig by setting:
#     NETCONFIG_DNS_POLICY=''
#
# See also the netconfig(8) manual page and other documentation.
#
### Call "netconfig update -f" to force adjusting of /etc/resolv.conf.
search lan
nameserver 192.168.1.240

nm-connection-editor won't let you define dns-over-tls hosts after the IP though.

This is a NetworkManager limitation that might be removed in the future, you can still add dns-over-tls hosts with a couple line of manual config files as explained in Arch wiki.

[Britoid]

Afaik it's a drop-in replacement as it's taking the DNS/domain list from /etc/resolv.conf, which is the standard way used by NetworkManager and others (also by systemd-networkd) to interact with current DNS daemons.
https://wiki.archlinux.org/index.php...#Automatically

It looks like on this proposal, they're going to make /etc/resolv.conf link to the stub-resolver, so anything reading /etc/resolv.conf talks to resolved instead, which then has its own configuration.

But, CommunityMember is saying above its possible for NetworkManager to tell systemd-resolved what DNS servers to

Edit: So NetworkManager does seem to tell resolved what dns servers to use per-connection. Had to scroll do the bottom of resolvectl status. nm-connection-editor won't let you define dns-over-tls hosts after the IP though.