Public bug reported: I have a full-disk-encryption Ubuntu box (in fact it's a Raspberry Pi 3) set up with Dropbear in its initramfs so that I can ssh in and type the disk-encryption passphrase.
But I've noticed that when I ssh in to the initramfs, the device has a different IP address than it gets once it's booted fully. This appears to be because the initramfs dhcpcd uses a different DHCP client identifier than systemd-networkd does in the booted system. This in turn appears to be because /usr/share/initramfs- tools/hooks/dhcpcd sets the "duid ll" option, forcing the use of a RFC4631 client identifier (with DUID) https://datatracker.ietf.org/doc/html/rfc4361#section-6.1 and yet /usr/share/initramfs-tools/scripts/functions (in _render_netplan) sets up a netplan override including the option "dhcp-identifier: mac" which forces the use of a RFC2313 client identifier (plain HW type and MAC address). As the two DHCP sessions (initramfs and booted-system) have different client IDs, the DHCP server (which is a perfectly normal OpenWRT 22.03.3 installation) gives the sessions different IP addresses. I can work around this at the DHCP server end by assigning a specific IP address to the *MAC address* (which stays the same) as opposed to the *client identifier* (which doesn't), but this is definitely a bug at the client end. Ubuntu version on the Pi is 24.04.2 LTS, initramfs-tools-core package is 0.142ubuntu25.5. ProblemType: Bug DistroRelease: Ubuntu 24.04 Package: initramfs-tools-core 0.142ubuntu25.5 ProcVersionSignature: Ubuntu 6.8.0-57.59-generic 6.8.12 Uname: Linux 6.8.0-57-generic x86_64 ApportVersion: 2.28.1-0ubuntu3.5 Architecture: amd64 CasperMD5CheckResult: unknown CurrentDesktop: KDE Date: Fri May 2 16:22:21 2025 EcryptfsInUse: Yes InstallationDate: Installed on 2017-04-02 (2952 days ago) InstallationMedia: Kubuntu 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215) PackageArchitecture: all RebootRequiredPkgs: Error: path contained symlinks. SourcePackage: initramfs-tools UpgradeStatus: Upgraded to noble on 2025-03-15 (48 days ago) ** Affects: initramfs-tools (Ubuntu) Importance: Undecided Status: New ** Tags: apport-bug noble -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2109847 Title: initramfs DHCP uses inconsistent client IDs To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/2109847/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
