Service clients that perform "SRV" lookups

Jonathan de Boyne Pollard J.deBoynePollard at Tesco.NET
Fri Dec 10 04:40:56 UTC 2004

KD> However, SRV record support hasn't even made it into
KD> web browsers yet, let alone clients of less-common protocols...

Actually, it's the other way around. The clients of the less-common 
protocols sometimes make good use of "SRV" lookups.  Modern WHOIS 
clients will make "_nicname._tcp" "SRV" resource record lookups to find 
the correct WHOIS server, for example, and a fair number of registries 
(Nominet, AFNIC, AUNIC, DENIC, SIDN, NASK, NORID, IEDR, and so forth) 
now support this.  Similarly, the LDAP clients in Microsoft and Linux 
softwares perform "_ldap._tcp" "SRV" lookups to locate LDAP servers.

Whereas it is the web browsers and proxy HTTP servers that are the 
holdouts, to the shame and embarrassment of their authors.  The work 
item to add "SRV" support to Mozilla has now languished for 5 years.  
Squid doesn't yet employ "SRV" lookups, either.  And whilst Microsoft 
Windows Server networking is an exemplar that many point to when 
discussing the use of "SRV" resource records, Microsoft's Windows 2000 
Resource Kit even gives examples of "_http._tcp" "SRV" resource records, 
and the suggestion having been on Microsoft's suggestions list for a 
couple of years now, Microsoft's own Internet Explorer *still* does not 
perform "SRV" lookups.


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