On Ubuntu 20.04 (systemd v245.4-4ubuntu3.21), hostname resolution only follows 8 CNAME redirections maximum.
So when using a service like Azure Virtual Desktop that has between 9 and 12 redirections, name resolution fails.
$ host client.wvd.microsoft.com
Host client.wvd.microsoft.com not found: 2(SERVFAIL)
$ resolvectl query client.wvd.microsoft.com
client.wvd.microsoft.com: resolve call failed: CNAME loop detected, or CNAME resolving disabled on 'waws-prod-zrh-ff7172dd.sip.p.azurewebsites.windows.net'
On the other hand it's working fine on Ubuntu 20.04 because CNAME loop limit has been raised from 8 to 16.
$ host client.wvd.microsoft.com
client.wvd.microsoft.com is an alias for client.privatelink-global.wvd.microsoft.com.
client.privatelink-global.wvd.microsoft.com is an alias for client.privatelink.wvd.microsoft.com.
client.privatelink.wvd.microsoft.com is an alias for rdweb.wvd.microsoft.com.
rdweb.wvd.microsoft.com is an alias for rdweb.privatelink-global.wvd.microsoft.com.
rdweb.privatelink-global.wvd.microsoft.com is an alias for rdweb.privatelink.wvd.microsoft.com.
rdweb.privatelink.wvd.microsoft.com is an alias for rdweb-prod-geo.trafficmanager.net.
rdweb-prod-geo.trafficmanager.net is an alias for mrs-chnor1c101-rdweb-prod.wvd-ase-chnor1c101-prod.p.azurewebsites.net.
mrs-chnor1c101-rdweb-prod.wvd-ase-chnor1c101-prod.p.azurewebsites.net is an alias for waws-prod-zrh-63daa049.sip.p.azurewebsites.windows.net.
waws-prod-zrh-63daa049.sip.p.azurewebsites.windows.net is an alias for waws-prod-zrh-63daa049.cloudapp.net.
waws-prod-zrh-63daa049.cloudapp.net has address 51.107.69.35
Here's a quick fix that raises the max CNAME limit from 8 to 16 like it is in Ubuntu 22.04, it fixes the problem for me.
On Ubuntu 20.04 (systemd v245.4- 4ubuntu3. 21), hostname resolution only follows 8 CNAME redirections maximum.
So when using a service like Azure Virtual Desktop that has between 9 and 12 redirections, name resolution fails.
$ host client. wvd.microsoft. com wvd.microsoft. com not found: 2(SERVFAIL) wvd.microsoft. com wvd.microsoft. com: resolve call failed: CNAME loop detected, or CNAME resolving disabled on 'waws-prod- zrh-ff7172dd. sip.p.azurewebs ites.windows. net'
Host client.
$ resolvectl query client.
client.
On the other hand it's working fine on Ubuntu 20.04 because CNAME loop limit has been raised from 8 to 16.
$ host client. wvd.microsoft. com wvd.microsoft. com is an alias for client. privatelink- global. wvd.microsoft. com. privatelink- global. wvd.microsoft. com is an alias for client. privatelink. wvd.microsoft. com. privatelink. wvd.microsoft. com is an alias for rdweb.wvd. microsoft. com. microsoft. com is an alias for rdweb.privateli nk-global. wvd.microsoft. com. nk-global. wvd.microsoft. com is an alias for rdweb.privateli nk.wvd. microsoft. com. nk.wvd. microsoft. com is an alias for rdweb-prod- geo.trafficmana ger.net. geo.trafficmana ger.net is an alias for mrs-chnor1c101- rdweb-prod. wvd-ase- chnor1c101- prod.p. azurewebsites. net. rdweb-prod. wvd-ase- chnor1c101- prod.p. azurewebsites. net is an alias for waws-prod- zrh-63daa049. sip.p.azurewebs ites.windows. net. zrh-63daa049. sip.p.azurewebs ites.windows. net is an alias for waws-prod- zrh-63daa049. cloudapp. net. zrh-63daa049. cloudapp. net has address 51.107.69.35
client.
client.
client.
rdweb.wvd.
rdweb.privateli
rdweb.privateli
rdweb-prod-
mrs-chnor1c101-
waws-prod-
waws-prod-
Here's a quick fix that raises the max CNAME limit from 8 to 16 like it is in Ubuntu 22.04, it fixes the problem for me.
Best regards,
Vincent.
--- systemd- 245.4.ORIG/ src/resolve/ resolved- dns-query. c 2023-06-15 16:58:25.454156663 +0200 245.4/src/ resolve/ resolved- dns-query. c 2023-06-01 14:30:09.000000000 +0200 etc-hosts. h"
+++ systemd-
@@ -10,7 +10,7 @@
#include "resolved-
#include "string-util.h"
-#define CNAME_MAX 8 QUERIES_ MAX 64
+#define CNAME_MAX 16
#define QUERIES_MAX 2048
#define AUXILIARY_
ProblemType: Bug sysctl. d/50-default. conf] ature: Ubuntu 5.19.0- 42.43~22. 04.1-generic 5.19.17 dules: nvidia_modeset nvidia esult: unknown installer/ media-info' /vmlinuz- 5.19.0- 42-generic root=/dev/ mapper/ AmadeUbuntu22- root ro apparmor=1 security=apparmor audit=1 acpi_rev_override load_nvme=YES nouveau.modeset=0 dis_ucode_ldr quiet splash :bvr1.25. 0:bd11/ 21/2022: br1.25: svnDellInc. :pnLatitude5591 :pvr:rvnDellInc .:rn0DVVG1: rvrA00: cvnDellInc. :ct10:cvr: sku0819: conffile. .etc.cron. daily.apport: [deleted] .etc.systemd. journald. conf: 2022-11- 22T13:40: 37.558934
DistroRelease: Ubuntu 22.04
Package: systemd 249.11-0ubuntu3.9 [modified: usr/lib/
ProcVersionSign
Uname: Linux 5.19.0-42-generic x86_64
NonfreeKernelMo
ApportVersion: 2.20.11-0ubuntu82.5
Architecture: amd64
CasperMD5CheckR
CurrentDesktop: ubuntu:GNOME
Date: Thu Jun 15 16:53:19 2023
InstallationDate: Installed on 2022-11-22 (205 days ago)
InstallationMedia: Error: [Errno 13] Permission denied: '/var/log/
MachineType: Dell Inc. Latitude 5591
ProcKernelCmdLine: BOOT_IMAGE=
RebootRequiredPkgs: Error: path contained symlinks.
SourcePackage: systemd
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/21/2022
dmi.bios.release: 1.25
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.25.0
dmi.board.name: 0DVVG1
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.
dmi.product.family: Latitude
dmi.product.name: Latitude 5591
dmi.product.sku: 0819
dmi.sys.vendor: Dell Inc.
modified.
mtime.conffile.