SRV Request to DNS

[Barry Margolin]

In article <mailman.2812.1444767618.26362.bind-users at lists.isc.org>,
 Mark Andrews <marka at isc.org> wrote:

> To answer the question.  What you do when given a name and a port
> is protocol specific.  Read the protocol specification.  Note if
> the port is the well known port for the protocol then it may be
> ignored.
> 
> If the protocol does not specify most developers will just implement
> the protocol over that port to the specified host taking into account
> well known ports if needed.
> 
> To used SRV with a protocol you need a specification that says to
> do so.  Using SRV without such a specification results in undefined
> behaviour.

Are there *any* current, well-known protocols that make use of SRV 
records to find the port? The examples I've seen just use it to find a 
server (analogous to the way MX records are used for mail).

Theoretically, this could be useful for HTTP, so you wouldn't have to 
put :port# in URLs if the domain uses an alternate port. It would make 
things easier when you have servers for multiple domains behind a NAT 
router with a single public address. But AFAIK there's been no movement 
to require browsers to use SRV for this.

-- 
Barry Margolin
Arlington, MA