On Tue Aug 16 09:47:35 2011, Kevin Smith wrote:
On Mon, Aug 15, 2011 at 8:44 AM, Dave Cridland <d...@cridland.net>
wrote:
> On Sat Aug 13 23:34:56 2011, Josemar Müller Lohn wrote:
>>> Is it valid to so:
>>> _xmpp-client._tcp.alice.com. CNAME _xmpp-client.bob.com.
>>
>> You can only get a CNAME answer when you ask for an A record.
>
> I don't think that's true.
>
> I think it may well choke the resolvers in many XMPP
implementations, mind,
> but I think it ought to work according to the specifications. A
CNAME merely
> states to restart the resolution using the new name.
>
> Specifically, the requirement that a name with a CNAME record
MUST NOT have
> any other records (aside from certain DNSSEC ones) would appear
to support
> that.
Is this true? My understanding was that the target for an SRV record
explicitly could not be a CNAME, and that the lookup done by XMPP
was
explicitly SRV. (That is: I don't believe it's valid)
The RHS of a SRV cannot have a CNAME record, but I think a SRV lookup
can legitimately return a CNAME.
So:
_xmpp-client._tcp.alice.com. CNAME _xmpp-client._tcp.bob.com.
_xmpp-client._tcp.bob.com. SRV 1 0 5222 xmpp.bob.com.
Is legal, whereas:
_xmpp-client._tcp.alice.com. SRV 1 0 522 xmpp.alice.com.
xmpp.alice.com. CNAME xmpp.bob.com.
Is not.
Dave.
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