Re: A web of directories

[Michael Helm <helm@xxxxxxxxxxxx>]

"Bob Jueneman" writes:
> 1.  How widely is the SRV function deployed?  Is it standardized
> (RFC ?), what vendors support it,

> 	It was deployed in the Vixie BIND code about 3 years back.

It's certainly in bind 8.x.
Also, it is essential for NT 5 / Windows 2000 so it must be in
microsoft's DNS.

(from the rfc index)

2052 A DNS RR for specifying the location of services (DNS SRV). A.
     Gulbrandsen, P. Vixie. October 1996. (Format: TXT=19257 bytes)
     (Status: EXPERIMENTAL)

http://www.es.net/pub/rfcs/rfc2052.txt
& the usual places


> 2.  Can the SRV deal with multiple protocols?  If it doesn't
> already, could it be extended? In particular, for what I am trying to
> negotiate what directory access protocol they use, e.g., LDAP, DAP,
> NDAP (NDS), HTTP, FTP, or whatever.  Would this work?  

Absolutely -- at least according to the spec.  See the rfc.
Don't have any practical experience with it.


Some examples from the RFC:

   Here is the format of the SRV RR, whose DNS type code is 33:
 
        Service.Proto.Name TTL Class SRV Priority Weight Port Target

Introductory example
 
   When a SRV-cognizant web-browser wants to retrieve
 
      http://www.asdf.com/
 
   it does a lookup of
 
      http.tcp.www.asdf.com

More complex ones in the RFC itself.   Obviously your client application
would have to handle sorting thru whatever the SRV returned if 
you get multiple hits for a protocol, somewhat like the way MX
records are handled.