OSX Domain-Specific DNS Servers (/etc/resolver)

If you VPN to work from home (or even VPN to home from work ;-)), you may have issues resolving hostnames. A good way to solve this issue is to use the /etc/resolver folder. If you have DNS set up, you can assign specific domains to be resolved by specific name servers. To implement, simply create a file in the /etc/resolver folder with the same name as the domain you want to configure:

# cd /etc/resolver
# sudo touch mydomain.com
# sudo touch myotherdomain.com
# ls -la
drwxr-xr-x    5 root  wheel   170 Sep 13 10:17 .
drwxr-xr-x  101 root  wheel  3434 Jan 25 17:10 ..
-rw-r--r--    1 root  wheel    45 Jan 30 12:49 mydomain.com
-rw-r--r--    1 root  wheel    72 Jan 30 10:45 myotherdomain.com

Then, within each file, include the DNS servers you wish to resolve against that domain:

# sudo sh -c 'echo "nameserver" >> mydomain.com'
# sudo sh -c 'echo "nameserver" >> myotherdomain.com'

NOTE: The sudo sh -c '<cmd>' is necessary to run the redirection with the correct privileges. See this thread.