[Bug 1971535] [NEW] systemd-resolved doesn't work properly for VPN connection

[Artur]

Public bug reported:

I'm using network-manager-openconnect-gnome (Cisco AnyConnect with certificate authentication).
When VPN connection is established local addresses cannot be resolved by systemd-resolved.
Content of /etc/resolv.conf:
   nameserver 127.0.0.53
   options edns0 trust-ad
   search 10.65.206.5

Content of /run/systemd/resolve/stub-resolv.conf:
   nameserver 127.0.0.53
   options edns0 trust-ad
   search 10.65.206.5

Content of /run/systemd/resolve/resolv.conf:
   nameserver 10.65.206.5
   search 10.65.206.5

If I change nameserver to 10.65.206.5 in /etc/resolv.conf local
addresses resolv works OK!

Output of dnstracer is in attached file: dnstracer_v_vs.txt.

If I set DNS server address to 10.65.206.2 everything work OK, output of
dnstracer with server specified is in attached file: dnstracer_v_vs.txt.

For previous LTS it's working without problems.
Clean install of Ubuntu 20.04.4 LTS - no problem.
Clean install of Ubuntu 22.04 LTS - resolv problem.

** Affects: systemd (Ubuntu)
     Importance: Undecided
         Status: New

** Attachment added: "output of dnstracer webmail.abc.local -v and dnstracer webmail.abc.local -vs 10.65.206.2"
   https://bugs.launchpad.net/bugs/1971535/+attachment/5586537/+files/dnstracer_v_vs.txt

** Description changed:

  I'm using network-manager-openconnect-gnome (Cisco AnyConnect with certificate authentication).
  When VPN connection is established local addresses cannot be resolved by systemd-resolved.
  Content of /etc/resolv.conf:
-    nameserver 127.0.0.53
-    options edns0 trust-ad
-    search 10.65.206.5
+    nameserver 127.0.0.53
+    options edns0 trust-ad
+    search 10.65.206.5
  
  Content of /run/systemd/resolve/stub-resolv.conf:
-    nameserver 127.0.0.53
-    options edns0 trust-ad
-    search 10.65.206.5
+    nameserver 127.0.0.53
+    options edns0 trust-ad
+    search 10.65.206.5
  
  Content of /run/systemd/resolve/resolv.conf:
-    nameserver 10.65.206.5
-    search 10.65.206.5
+    nameserver 10.65.206.5
+    search 10.65.206.5
  
  If I change nameserver to 10.65.206.5 in /etc/resolv.conf local
  addresses resolv works OK!
  
- Output of dnstracer is in attached file: dnstracer_v.txt.
+ Output of dnstracer is in attached file: dnstracer_v_vs.txt.
  
  If I set DNS server address to 10.65.206.2 everything work OK, output of
  dnstracer with server specified is in attached file: dnstracer_vs.txt.
  
  For previous LTS it's working without problems.
  Clean install of Ubuntu 20.04.4 LTS - no problem.
  Clean install of Ubuntu 22.04 LTS - resolv problem.

** Description changed:

  I'm using network-manager-openconnect-gnome (Cisco AnyConnect with certificate authentication).
  When VPN connection is established local addresses cannot be resolved by systemd-resolved.
  Content of /etc/resolv.conf:
     nameserver 127.0.0.53
     options edns0 trust-ad
     search 10.65.206.5
  
  Content of /run/systemd/resolve/stub-resolv.conf:
     nameserver 127.0.0.53
     options edns0 trust-ad
     search 10.65.206.5
  
  Content of /run/systemd/resolve/resolv.conf:
     nameserver 10.65.206.5
     search 10.65.206.5
  
  If I change nameserver to 10.65.206.5 in /etc/resolv.conf local
  addresses resolv works OK!
  
  Output of dnstracer is in attached file: dnstracer_v_vs.txt.
  
  If I set DNS server address to 10.65.206.2 everything work OK, output of
- dnstracer with server specified is in attached file: dnstracer_vs.txt.
+ dnstracer with server specified is in attached file: dnstracer_v_vs.txt.
  
  For previous LTS it's working without problems.
  Clean install of Ubuntu 20.04.4 LTS - no problem.
  Clean install of Ubuntu 22.04 LTS - resolv problem.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to systemd in Ubuntu.
https://bugs.launchpad.net/bugs/1971535

Title:
  systemd-resolved doesn't work properly for VPN connection

Status in systemd package in Ubuntu:
  New

Bug description:
  I'm using network-manager-openconnect-gnome (Cisco AnyConnect with certificate authentication).
  When VPN connection is established local addresses cannot be resolved by systemd-resolved.
  Content of /etc/resolv.conf:
     nameserver 127.0.0.53
     options edns0 trust-ad
     search 10.65.206.5

  Content of /run/systemd/resolve/stub-resolv.conf:
     nameserver 127.0.0.53
     options edns0 trust-ad
     search 10.65.206.5

  Content of /run/systemd/resolve/resolv.conf:
     nameserver 10.65.206.5
     search 10.65.206.5

  If I change nameserver to 10.65.206.5 in /etc/resolv.conf local
  addresses resolv works OK!

  Output of dnstracer is in attached file: dnstracer_v_vs.txt.

  If I set DNS server address to 10.65.206.2 everything work OK, output
  of dnstracer with server specified is in attached file:
  dnstracer_v_vs.txt.

  For previous LTS it's working without problems.
  Clean install of Ubuntu 20.04.4 LTS - no problem.
  Clean install of Ubuntu 22.04 LTS - resolv problem.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1971535/+subscriptions