I've just seen this issue the first time on a Ubuntu 20.04 (updated several months ago from 16.04) AWS EC2 machine. Looking closer into this, the machine lost its IP address multiple times in the last hours. The following avahi-daemon log messages made me find this bug report:
ck@focal:~$ grep avahi-daemon /var/log/syslog | grep -i withdrawing Jan 18 20:17:42 inf-mon04-p avahi-daemon[941]: Withdrawing address record for 10.10.1.41 on eth0. Jan 18 21:44:52 inf-mon04-p avahi-daemon[941]: Withdrawing address record for 10.10.1.41 on eth0. It's very interesting, that both of these events happened EXACTLY one hour after the system boot: ck@focal:~$ last | head ck pts/0 xx.xx.xx.xxx Tue Jan 18 22:11 still logged in root ttyS0 Tue Jan 18 21:50 still logged in reboot system boot 5.4.0-91-generic Tue Jan 18 20:44 still running reboot system boot 5.4.0-91-generic Tue Jan 18 19:17 - 20:39 (01:22) Running "dhclient" on the EC2 console, as suggested in comment #46, re- assigns the IP address. Relevant versions installed: ck@focal:~$ dpkg -l|egrep "(dhcp|network-manager)" ii isc-dhcp-client 4.4.1-2.1ubuntu5.20.04.2 amd64 DHCP client for automatically obtaining an IP address ii isc-dhcp-common 4.4.1-2.1ubuntu5.20.04.2 amd64 common manpages relevant to all of the isc-dhcp packages ii network-manager 1.22.10-1ubuntu2.2 amd64 network management framework (daemon and userspace tools) ii network-manager-gnome 1.8.24-1ubuntu3 amd64 network management framework (GNOME frontend) ii network-manager-pptp 1.2.8-2 amd64 network management framework (PPTP plugin core) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1586528 Title: Avahi-daemon withdraws address record To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/avahi/+bug/1586528/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
