iTunes remote sharing

I've been trying to get iTunes to stream music across the internet but to no avail.

The iTunes library is on an iMac and I can stream the music to a MacBook Pro when
both are on the same network.

I've tried using SSH from the MacBook to the iMac when on a different network and
it appears to work as I get challenged for the password.

I've used DNS-DS on the MacBook to address the Bonjour broadcast issue.

No obvious errors from either SSH or DNS-DS.

So my question is has anyone got Music sharing (not Home Sharing) to work across
the internet using iTunes 12 running on Yosemite