====== Ubuntu - VPN - OpenVPN - Configure OpenVPN to resolve local DNS & hostnames ======

To allow accessing local computers on the LAN by their hostnames instead of just by IP Address.

<WRAP info>
**NOTE:**  By default, the client **resolv.conf** file does not contain a line to point the client to the VPN DNS server; nor does it contain a line telling the client what the local domain name is.

  * Adding these lines (and removing when VPN is down) to resolv.conf automatically is the goal. 

</WRAP>

----

===== Server =====

Ensure the following lines are in the server config file **/etc/openvpn/server.conf**.

<file bash /etc/openvpn/server.conf>
push "dhcp-option DNS 192.168.1.1"
push "dhcp-option DOMAIN localdomain"
</file>

<WRAP info>
**NOTE:**  This tells the client that they should use 192.168.1.1 as the DNS server, and localdomain as a domain.
</WRAP>


----

===== Client =====

Install the **resolvconf** package to give your OpenVPN client the ability to rebuild the resolv.conf file when you start and stop your VPN connection.

This also backups the existing resolv.conf file; and creates a symlink to the resolv.conf file.

<code bash>
sudo apt install resolvconf
sudo mv /etc/resolv.conf /etc/resolv.conf.orig
sudo ln -s /run/resolvconf/resolv.conf /etc/resolv.conf
</code>

Add the following lines to the client .ovpn file.

<file bash>
up /etc/openvpn/update-resolv-conf
down /etc/openvpn/update-resolv-conf
</file>

<WRAP info>
**NOTE:**  This will run **update-resolv-conf** every time the client connects to or disconnects from the VPN server.
</WRAP>


----

===== Test =====

Run the openvpn command with **<nowiki>--script-security 2</nowiki>** flag to allow update-resolv-conf to be run:

<code bash>
sudo openvpn --script-security 2 --config /path/to/client.ovpn
</code>

----

===== References =====

https://steamforge.net/wiki/index.php/How_to_configure_OpenVPN_to_resolve_local_DNS_%26_hostnames

http://www.softwarepassion.com/solving-dns-problems-with-openvpn-on-ubuntu-box/

https://serverfault.com/questions/318563/how-to-push-my-own-dns-server-to-openvpn