====== Ubuntu - VPN - ExpressVPN - Revert to internal DNS upon ExressVPN disconnect ======

ExpressVPN has a bug in that it does not revert the /etc/resolv.conf DNS settings back to the internal one when the VPN is disonnected.

  * This results in internet queries still trying to use the ExpressVPN DNS, which is cannot access due to the VPN being off.

----

===== Disconnect from ExpressVPN =====

<code bash>
expressvpn disconnect
</code>

----

===== Check which DNS server is being used =====

<code bash>
systemd-resolve --status
</code>

returns:

<code bash>
Global
       LLMNR setting: no
MulticastDNS setting: no
  DNSOverTLS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
  Current DNS Server: 10.100.0.1
         DNS Servers: 10.100.0.1
          DNS Domain: expressvpn
</code>

<WRAP info>
**NOTE:**  The **Current DNS Server** line should be pointing to the internal DNS, but here it shows this still points to the ExpressVPN DNS even though the VPN is disconnected.
</WRAP>

----

===== Fix this issue =====

==== Check the status of the systemd-resolv service ====

<code bash>
sudo systemctl status systemd-resolved.service
</code>

returns:

<code bash>
● systemd-resolved.service - Network Name Resolution
     Loaded: loaded (/lib/systemd/system/systemd-resolved.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 2022-03-17 19:28:19 GMT; 4 days ago
       Docs: man:systemd-resolved.service(8)
             https://www.freedesktop.org/wiki/Software/systemd/resolved
             https://www.freedesktop.org/wiki/Software/systemd/writing-network-configuration-managers
             https://www.freedesktop.org/wiki/Software/systemd/writing-resolver-clients
   Main PID: 1160 (systemd-resolve)
     Status: "Processing requests..."
      Tasks: 1 (limit: 77016)
     Memory: 7.6M
     CGroup: /system.slice/systemd-resolved.service
             └─1160 /lib/systemd/systemd-resolved

Mar 17 19:28:19 bigmamba systemd[1]: Starting Network Name Resolution...
Mar 17 19:28:19 bigmamba systemd-resolved[1160]: Positive Trust Anchors:
Mar 17 19:28:19 bigmamba systemd-resolved[1160]: . IN DS 20326 8 2 e06d44b80b8f1d39a95c0b0d7c65d08458e880409bbc683457104237c7f8ec8d
Mar 17 19:28:19 bigmamba systemd-resolved[1160]: Negative trust anchors: 10.in-addr.arpa 16.172.in-addr.arpa 17.172.in-addr.arpa 18.172.in-addr.arpa 19.172.in-addr.arpa 20.172.in-addr.arpa 21.172.in-addr.arpa 22.172.in-addr.arpa 23.172.in-addr.arpa 24.172.in-addr.arpa 25.172.in-addr.arpa 26.172.in-addr.arpa 27.172.in-addr.arpa 28.172.in-addr.arpa 29.172.in-addr.arpa 30.172.in->
Mar 17 19:28:19 bigmamba systemd-resolved[1160]: Using system hostname 'bigmamba'.
Mar 17 19:28:19 bigmamba systemd[1]: Started Network Name Resolution.
Mar 17 19:30:37 bigmamba systemd-resolved[1160]: Flushed all caches.
Mar 20 10:47:01 bigmamba systemd-resolved[1160]: Flushed all caches.
</code>

<WRAP info>
**NOTE:**  This shows the service is running.  Good.
</WRAP>

----

==== Restart the systemd-resolv service ====

<code bash>
sudo systemctl restart systemd-resolved.service
</code>

----

===== Check again which DNS server is being used =====

<code bash>
systemd-resolve --status
</code>