Without immediately addressing what has later been discussed in this thread, I should probably clarify what I meant in my original post. On Sat, Jan 3, 2015 at 10:12 PM, John C Klensin <john-ietf@xxxxxxx> wrote: > If I understand the above part of your comments correctly, "one > A/AAAA record..." hasn't been necessary since HTTP 1.1 > introduced the HTTP "host" verb. That was a lesson we learned > from SMTP, FTP, and elsewhere -- virtual hosts should not > require separate (either physical or virtual) interfaces and > addresses. With the introduction of the Host header, virtual hosts indeed do not require new interfaces or addresses, be they physical or virtual. Regardless of this, if I was to request <http://foo.example/> using a current HTTP/1.1 user agent, the AAAA and/or A records for foo.example. would be queried, potentially using the Happy Eyeballs algorithm. If the entity behind foo.example. wanted to run their primary HTTP service on a host other than the one indicated by the AAAA or A records, the closest solutions now would be to configure the host on the bare domain to either route or reverse proxy to the real server. This may occur for example if foo.example. uses a shared web hosting provider, while wanting to serve HTTP as well as other protocols directly on their bare domain. The ability to use SRV records would eliminate the additional traffic and computational overhead required for routing or reverse proxying.