Public bug reported: netplan & networkd only use systemd-networkd's default of DuplicateAddressDetection=ipv6, thus not checking for IPv4 conflicts.
From what I know RedHat based systems on the other hand use the arping tool during ifup in their ifcfg system (ARPCHECK=yes by default) to check for IP conflicts. In order to reach a similar result in Ubuntu, we would need to place an override configuration snippet in /etc/systemd/network/10-netplan-eth0.network.d/override.conf, specifying an [Address] section and corresponding DuplicateAddressDetection=both setting for each IP address [0]. This is probably even something that netplan should be doing by default, but it is not currently. [0] https://www.freedesktop.org/software/systemd/man/systemd.network.html#DuplicateAddressDetection= ** Affects: netplan Importance: Wishlist Status: New ** Affects: netplan.io (Ubuntu) Importance: Undecided Status: New ** Changed in: netplan Importance: Undecided => Wishlist ** Also affects: netplan.io (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1959190 Title: Support DuplicateAddressDetection by default To manage notifications about this bug go to: https://bugs.launchpad.net/netplan/+bug/1959190/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
