Public bug reported:
After upgrading from Ubuntu 24.04 (systemd 255) to Ubuntu 26.04 (systemd
259), DHCP-provided domain information is no longer being applied as a
DNS search domain.
Environment:
- Ubuntu 26.04
- systemd 259.5-0ubuntu3.4
- netplan.io 1.2-1ubuntu5.1
- DHCP via systemd-networkd/netplan
DHCP is correctly supplying Option 15 (Domain Name):
Domain-Name (15): stpaul.sk.ca
The lease file confirms the value is received:
DOMAINNAME=stpaul.sk.ca
However, no search domain is configured:
$ resolvectl domain eth0
Link 2 (eth0):
As a result, short-name lookups fail:
$ resolvectl query cja01
resolve call failed: No appropriate name servers or networks for name found
while FQDN lookups succeed:
$ resolvectl query cja01.stpaul.sk.ca
For comparison, Ubuntu 24.04 (systemd 255) on the same DHCP
infrastructure successfully resolves short names using the same DHCP
configuration.
Expected:
The DHCP-provided domain name (stpaul.sk.ca) should be applied as a DNS search
domain, allowing single-label hostnames to resolve.
Actual:
The DHCP domain name is present in the lease but is not applied as a search
domain, causing single-label hostname resolution to fail.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: systemd 259.5-0ubuntu3.4
ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14
Uname: Linux 7.0.0-38-generic x86_64
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
CasperMD5CheckResult: pass
CloudArchitecture: x86_64
CloudID: none
CloudName: none
CloudPlatform: none
CloudSubPlatform: config
CurrentDmesg: Error: command ['dmesg'] failed with exit code 1: dmesg: read
kernel buffer failed: Operation not permitted
Date: Wed Oct 7 17:10:30 2026
InstallationDate: Installed on 2024-03-20 (931 days ago)
InstallationMedia: Ubuntu-Server 22.04.4 LTS "Jammy Jellyfish" - Release amd64
(20240216.1)
Lspci:
Lspci-vt:
Lsusb: Error: command ['lsusb'] failed with exit code 1:
Lsusb-t:
Lsusb-v: Error: command ['lsusb', '-v'] failed with exit code 1:
MachineType: Microsoft Corporation Virtual Machine
ProcEnviron:
LANG=C.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-38-generic
root=/dev/mapper/ubuntu--vg-ubuntu--lv ro
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
SourcePackage: systemd
SystemdFailedUnits:
Error: command ['systemctl', 'status', '--full', '●'] failed with exit code 4:
Invalid unit name "●" escaped as "\xe2\x97\x8f" (maybe you should use
systemd-escape?).
Unit \xe2\x97\x8f.service could not be found.
------
Error: command ['systemctl', 'status', '--full', '●'] failed with exit code 4:
Invalid unit name "●" escaped as "\xe2\x97\x8f" (maybe you should use
systemd-escape?).
Unit \xe2\x97\x8f.service could not be found.
UpgradeStatus: Upgraded to resolute on 2026-10-07 (0 days ago)
acpidump:
dmi.bios.date: 10/24/2025
dmi.bios.release: 4.1
dmi.bios.vendor: Microsoft Corporation
dmi.bios.version: Hyper-V UEFI Release v4.1
dmi.board.asset.tag: None
dmi.board.name: Virtual Machine
dmi.board.vendor: Microsoft Corporation
dmi.board.version: Hyper-V UEFI Release v4.1
dmi.chassis.asset.tag: 2155-1607-5336-2400-6812-8557-05
dmi.chassis.type: 3
dmi.chassis.vendor: Microsoft Corporation
dmi.chassis.version: Hyper-V UEFI Release v4.1
dmi.modalias:
dmi:bvnMicrosoftCorporation:bvrHyper-VUEFIReleasev4.1:bd10/24/2025:br4.1:svnMicrosoftCorporation:pnVirtualMachine:pvrHyper-VUEFIReleasev4.1:rvnMicrosoftCorporation:rnVirtualMachine:rvrHyper-VUEFIReleasev4.1:cvnMicrosoftCorporation:ct3:cvrHyper-VUEFIReleasev4.1:skuNone:pfaVirtualMachine:
dmi.product.family: Virtual Machine
dmi.product.name: Virtual Machine
dmi.product.sku: None
dmi.product.version: Hyper-V UEFI Release v4.1
dmi.sys.vendor: Microsoft Corporation
** Affects: systemd (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute
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https://bugs.launchpad.net/bugs/2169876
Title:
Ubuntu 26.04 / systemd 259 no longer applies DHCP Option 15 (Domain
Name) as DNS search domain, causing single-label hostname resolution
failure
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