configd overwrites DNS and routing from OpenVPN

Apologies if this is covered elsewhere. I’ve looked and found no definitive answers.

Problem:

OpenVPN creates a tunnel on a virtual network interface tap0 which is configured via DHCP. Once up a script is called to update the routing tables and set DNS. On linux and windows this works and is very stable because static routing configurations are employed. On Mac OS X v10.6 routing configurations are dynamic and managed by configd. Once the virtual interface comes up the routing tables and DNS can be changed, but after a short while, configd will come along and change the routing and DNS configurations and break the VPN.

This is covered in some detail in this article.
https://www.afp548.com/article.php?story=20041015131913324

Question: How to write the DNS and routing entries into preferences at the time OpenVPN comes up so that they will persist when configd updates the system?

Details:

1. Commands used by OpenVPN script to update the routing table and DNS

/usr/sbin/ipconfig set “$dev” DHCP

/usr/sbin/scutil <