OS X Hybrid DNS

This is a collection of custom scripts I use with dnsmasq to use VPN DNS servers for a white list of search domains and use local network DNS configuration for all other lookups.

This allows DNS lookups on the local network to continue working and makes sure edge-cache DNS records use appropriate addresses for the location of the VPN client, instead of using ones that would be relevant to the VPN server.

Install

1. Clone this repository somewhere in your home directory
2. Install Homebrew
3. Run brew install ./Formula/dnsmasq-regex.rb (a patched version of dnsmasq that supports regular expressions)
4. cp -R dns-watch/ dnsmasq.available/ dnsmasq.enabled/ dnsmasq.conf /usr/local/etc
5. sudo launchctl load /usr/local/etc/dns-watch/io.eldredge.dns-watch.plist

Configure

• Edit /usr/local/etc/dnsmasq.available/local.conf with DNS records for localhost
• Edit /usr/local/etc/dns-watch/settings to choose mDNSResponder or discoveryd for Mavericks / Yosemite
• ln -s /usr/local/etc/dnsmasq.available/local.conf /usr/local/etc/dnsmasq.enabled

If you are using a ppp based VPN, do:

sudo mkdir /etc/ppp
sudo ln -s /usr/local/etc/dns-watch/local-dns /etc/ppp/ip-up
sudo ln -s /usr/local/etc/dns-watch/local-dns /etc/ppp/ip-down

Watch /var/log/dns-watch and look for lines like:

ActiveServices: A8227183-B047-4D4E-9BCE-490997F5030F 9D299D25-805E-449A-BC39-EC863A6E0C57

Make note of service IDs as you connect/disconnect your VPN.

For each service ID that correlates to a VPN that you want custom DNS settings for, create /usr/local/etc/dnsmasq.available/${SERVICE_ID}.profile

Example profile:

server=/localnet/10.0.0.1

This will instruct dnsmasq to send queries for the localnet domain to 10.0.0.1.