Manage DNS settings pushed from OpenVPN
This script is the Mac equivalent of Debian's /etc/openvpn/update-resolv-conf . It is based on the same
code, but uses networksetup instead of resolvconf to perform the work.
The name is therefore slightly misleading (it does not touch /etc/resolv.conf),
but using the same name lets us write OS-agnostic "up" and "down" directives in the client configuration.
To use, install /etc/openvpn/update-resolv-conf on the client Mac. You can then configure "up" and "down" directives in the openvpn client config file as follows:
script-security 2
up /etc/openvpn/update-resolv-conf
down /etc/openvpn/update-resolv-conf
In OpenVPN Access Server, set the following option in the server configuration to automatically add the above to the generated client files:
"vpn.client.config_text": "up /etc/openvpn/update-resolv-conf\ndown /etc/openvpn/update-resolv-conf",
Or equivalently, incant the following on the server command line:
/usr/local/openvpn_as/scripts/confdba -mk "vpn.client.config_text" -v "up /etc/openvpn/update-resolv-conf\ndown /etc/openvpn/update-resolv-conf"
Adapted from the original script here: https://github.com/masterkorp/openvpn-update-resolv-conf
networksetup invocation borrowed from https://blog.netnerds.net/2011/10/openvpn-update-client-dns-on-mac-os-x-using-from-the-command-line/