Validated for Jammy according to test case from description. No error messages were thrown, and networking has been correctly set up.
root@halves-lp1981103-j:~# ifdown enp5s0; ifup enp5s0 Killed old client process Internet Systems Consortium DHCP Client 4.4.1 Copyright 2004-2018 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/enp5s0/00:16:3e:bb:4d:57 Sending on LPF/enp5s0/00:16:3e:bb:4d:57 Sending on Socket/fallback DHCPRELEASE of 10.125.177.27 on enp5s0 to 10.125.177.1 port 67 (xid=0x4969e444) Internet Systems Consortium DHCP Client 4.4.1 Copyright 2004-2018 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/enp5s0/00:16:3e:bb:4d:57 Sending on LPF/enp5s0/00:16:3e:bb:4d:57 Sending on Socket/fallback DHCPDISCOVER on enp5s0 to 255.255.255.255 port 67 interval 3 (xid=0x787e8804) DHCPOFFER of 10.125.177.27 from 10.125.177.1 DHCPREQUEST for 10.125.177.27 on enp5s0 to 255.255.255.255 port 67 (xid=0x4887e78) DHCPACK of 10.125.177.27 from 10.125.177.1 (xid=0x787e8804) bound to 10.125.177.27 -- renewal in 1648 seconds. root@halves-lp1981103-j:~# dpkg -l | grep ifupdown ii ifupdown 0.8.36+nmu1ubuntu3.1 amd64 high level tools to configure network interfaces ** Tags removed: verification-needed-jammy ** Tags added: verification-done-jammy -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to ifupdown in Ubuntu. https://bugs.launchpad.net/bugs/1981103 Title: System with DNS server in /etc/network/interfaces has bogus systemd- resolved config after upgrade to 22.04 Status in ifupdown package in Ubuntu: Fix Released Status in ifupdown source package in Focal: Fix Released Status in ifupdown source package in Jammy: Fix Committed Status in ifupdown source package in Lunar: Fix Committed Bug description: [ Impact ] ifupdown configurations will stop having a working DNS server on upgrade [ Test Plan ] Upgrading from an Ubuntu 18.04 or earlier release, bounce a network interface with configured DNS server: root@pangaea-pm:~# ifdown ens13; ifup ens13 /etc/network/if-down.d/resolved: 12: mystatedir: not found /etc/network/if-up.d/resolved: 12: mystatedir: not found /etc/network/if-up.d/resolved: 71: DNS: not found /etc/network/if-up.d/resolved: 1: /run/network/ifupdown-inet-ens13: DNS=134.102.20.20 134.102.200.14: not found /etc/network/if-up.d/resolved: 2: /run/network/ifupdown-inet-ens13: DOMAINS=marum.de: not found Failed to parse DNS server address: DNS Failed to set DNS configuration: Invalid argument This should result in no errors, and in a valid network configuration with working DNS resolution. It's likely that existing netplan configuration needs to be removed and migrated to classic ifupdown scripts before running the test above. [ Where problems could occur ] Although we're only fixing the resolved scripts, more complex network setups might see regressions in DNS resolution for some cases. We should pay special attention to bridges or virtual interfaces that have been configured through ifupdown, as well as validate the other scripts under /etc/network/if-up.d/ [ Other Info ] Description: Ubuntu 22.04 LTS Release: 22.04 ifupdown: Installed: 0.8.36+nmu1ubuntu3 Candidate: 0.8.36+nmu1ubuntu3 Version table: *** 0.8.36+nmu1ubuntu3 500 500 http://de.archive.ubuntu.com/ubuntu jammy/universe amd64 Packages 100 /var/lib/dpkg/status After upgrading a server with classic ifupdown configuration after reboot the machine had no valid dns servers anymore. The problem is that the state file created by ifupdown using /etc/network/if-up.d/resolved looks like this: root@pangaea-pm:~# cat /run/network/ifupdown-inet-ens13 "DNS"="134.102.20.20 134.102.200.14" "DOMAINS"="marum.de" The script later sources this file and causes the following errors, easy to see when you execute this: root@pangaea-pm:~# ifdown ens13; ifup ens13 /etc/network/if-down.d/resolved: 12: mystatedir: not found /etc/network/if-up.d/resolved: 12: mystatedir: not found /etc/network/if-up.d/resolved: 71: DNS: not found /etc/network/if-up.d/resolved: 1: /run/network/ifupdown-inet-ens13: DNS=134.102.20.20 134.102.200.14: not found /etc/network/if-up.d/resolved: 2: /run/network/ifupdown-inet-ens13: DOMAINS=marum.de: not found Failed to parse DNS server address: DNS Failed to set DNS configuration: Invalid argument This happened to me on three different servers, so this is a serious bug and should be fixed before 22.04 upgrades are allowed for everybody. Most servers provided by data centers like Hetzner (Germany) are configure like that. After a do-release-upgrade you have no working DNS anymore, unless you disable systemd-resolved. I don't want to use netplan, so changing to this is no option. The fix is easy - remove the quotes in the script on the left side "$DNS" => $DNS; same for DOMAINS: if [ -n "$NEW_DNS" ]; then cat <<EOF >"$mystatedir/ifupdown-${ADDRFAM}-$interface" $DNS="$NEW_DNS" EOF if [ -n "$NEW_DOMAINS" ]; then cat <<EOF >>"$mystatedir/ifupdown-${ADDRFAM}-$interface" $DOMAINS="$NEW_DOMAINS" EOF fi fi To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1981103/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp