[Members] [news] Anyone can build a Windows Messenger client—with open standards access via XMPP

Dave Cridland dave at cridland.net
Wed Dec 21 11:25:10 UTC 2011

On Thu Dec 15 02:39:47 2011, jehan at zemarmot.net wrote:
> I'll note that they indeed have DNS SRV records for both client and
> server, though that gives back an alias (which — I think —is  
> wrong,
> though the RFC does not give this precise case. It says only one  
> should
> not return a target which is itself on alias; anyway we lose port,
> priority, weight, etc. information):
No, this is legal - any question may result in a CNAME answer, but  
you can't get an answer which refers to a CNAME. That is, looking up  
a record for the hostname returned by SRV cannot give you a CNAME,  
although asking for the SRV itself can do.

However, in this case, following the CNAME doesn't give you anything  
useful, so this is equivalent to no SRV record at all, and clients  
will presumably fail to connect. The docs are quite clear that  
clients have to connect to a specific hostname and port.

We can probably suggest to MSFT that they get the SRV records right;  
it's one less thing for client developers to need to do.

Dave Cridland - mailto:dave at cridland.net - xmpp:dwd at dave.cridland.net
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