http://verticalprogramming.com/2013/09/15/varnish-virtual-host-boilerplate
The "(req.http.host == "example1.com") " Pattern:
http://stackoverflow.com/questions/3334023/configure-multiple-sites-with-varnish
https://github.com/mattiasgeniar/varnish-4.0-configuration-templates/blob/master/default.vcl