Fedora 33 Planning To Enable Systemd-Resolved By Default

[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.

[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.

[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...?

[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

[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.

[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]

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).

[cjcox]

And remember, don't fork, contribute. Unless.... .... d.

[Mark Rose]

and in which version of systemd and when you had that problems ? Did you have any chance to give it a try to test if the problems still exist?

Ubuntu 18.04's packages, so systemd 237 and network-manager 1.10.6-2ubuntu1.4. It exists with the latest packages, and myself and coworkers have reproduced the bug on at least five different machines. https://bugs.launchpad.net/ubuntu/+s...r/+bug/1851407

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.

Except when it doesn't work at all. The solution we found was just getting rid of resolved: https://askubuntu.com/a/907249

[oiaohm]

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.

Except that does not in fact fix it just make the bug less frequent. Resolved does multi dns resolve so it walks down the DNS list very quickly. In fact shows a fault in your configuration that would normally be hidden. The fault with what you said add nameserver at top of resolv.conf under the past system was that if that DNS server did not respond for some reason old resolve system will walk down the list as well. Basically you need to set DNS priorities and you need to give directives that DHCP got DNS servers don't nuke you VPN ones. On business networks this can be setting particular domains to be resolved by particular DNS servers. Reality you need to do this bit with or without resolved.

https://github.com/systemd/systemd/issues/6076

Ubuntu 18.04's packages, so systemd 237 and network-manager 1.10.6-2ubuntu1.4. It exists with the latest packages, and myself and coworkers have reproduced the bug on at least five different machines. https://bugs.launchpad.net/ubuntu/+s...r/+bug/1851407

Except that bug says developers could not reproduce fault. And are asking if you missed ipv4.never-default=yes in all those cases. Yes not setting this in network manager and using the old resolve system still leaves you open to security bug just now requiring the first server not to respond triggering a walk down the list.

Basically resolved makes a fairly hidden bug caused by miss configuration happen really commonly and it cause is still miss configuration expect now people want to blame resolved instead of waking up o crap our configuration as been wrong all this time.