Hey,

Run into an error trying to use the sample ExampleMX() function in example_test.go:

It fails with the following error:
dial udp: address <my_v6_address>:53: too many colons in address

This is most likely due to r, _, err := c.Exchange(m, config.Servers[0]+":"+config.Port)
as my main resolver address is a V6 --
here's the excerpt from my resolv.conf (note: untouched, and OS X populated, so potentially highly reproducible):
`
search home

nameserver v6 address here

nameserver 192.168.1.1
`

Since the c.Exchange() function is trying config.Servers[0], it fails, as it expects the v6 address to be in [].