What

DNS server that replies the same address ("127.0.0.1" by default) to all type A queries and NXDOMAIN to any other query.

Why

It's often useful during development to access local services using a local domain. Existing options are:

1. Add them all to /etc/hosts (quickly becomes a mess, have to list all subdomains)
2. Run a DNS server like BIND (complex configuration)
3. Run a DNS proxy like Dnsmasq (reasonable option but still needs configuration)

Using devdns you just need to download a binary and run it. It works best with the OS X resolver system (see below).

How

Build (or download the OS X binary) and then run ./devdns. By default it listens on 127.0.0.1:5300 (UDP), you can specify an alternative address as follows: ./devdns -addr="127.0.0.1:6300".

On OS X you can use the resolver system (man 5 resolver) to resolve only a chosen few domains to this local server:

sudo mkdir -p /etc/resolver

# all domains ending in ".dev"
sudo vi /etc/resolver/dev

Contents of /etc/resolver/dev:

nameserver 127.0.0.1
port 5300

If you want to change the resolved address from the 127.0.0.1 default to another (virtual) machine you can change it as follows: ./devdns -ip="192.168.55.5".

Should you need to specify different resolved addresses for different host names you can run multiple instances of devdns on different listening addresses and change the /etc/resolver config accordingly. However at that point it might be easier to use Dnsmasq.

Building

Build using the standard go tools:

go get .
go build

Use go build -ldflags "-w" to build a version without debug symbols (smaller binary).