I found this bug report after experiencing the same problem. The error message I got was exactly the same as the one in comment #2. The fix suggested by Kazuhiro in comment #9 fixed the problem.
I think that since this bug affects more than one person, it's not merely a problem with one person's local environment. I didn't have occasion to use KVM between 2024-02-27 and today, but it was working for me before then and I didn't manually change anything in my environment. I don't know enough about Ubuntu networking to say whether it's a bug in dnsmasq or another component, but surely a package upgrade shouldn't break something like this. $ cat /var/log/apt/history.log.1 (snip) Start-Date: 2024-02-27 06:19:38 Commandline: /usr/bin/unattended-upgrade Upgrade: dnsmasq-base:amd64 (2.89-1, 2.90-0ubuntu0.23.10.1) End-Date: 2024-02-27 06:19:42 (snip) $ cat /etc/issue Ubuntu 23.10 \n \l $ virsh --version 9.6.0 $ /usr/sbin/dnsmasq --version Dnsmasq version 2.90 Copyright (c) 2000-2024 Simon Kelley Compile time options: IPv6 GNU-getopt DBus no-UBus i18n IDN2 DHCP DHCPv6 no-Lua TFTP conntrack ipset nftset auth cryptohash DNSSEC loop-detect inotify dumpfile This software comes with ABSOLUTELY NO WARRANTY. Dnsmasq is free software, and you are welcome to redistribute it under the terms of the GNU General Public License, version 2 or 3 $ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2055776 Title: After updating ubuntu, the network to which the subnet address is assigned does not become active in KVM. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dnsmasq/+bug/2055776/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
