Douglas Otis <dotis(_at_)mail-abuse(_dot_)org> wrote:
On Sat, 2005-07-02 at 16:48 -0400, John Leslie wrote:
I tend towards the 5xx, because it's a situation which will require
human intervention: the extra SRV record is not in the least likely to
go away by itself.
If there is a possibility of two RR appearing in a resolver due to a
record modification and some overlap in the TTL of old to new, then:
451 Requested action aborted: local error in processing
would address this error and not require any intervention for the
problem to be resolved.
At first blush, I don't see how this would happen. The (duplicate)
RRs have to have come from some DNS server: I don't offhand see how
they would have originated except from a single DNS server configured
with both.
I quite agree there will be record modifications; but the server
will serve a consitent set, both before and after update. Intermediate
servers will receive a consistent set. Et cetera.
I also tend towards 5xx because 4xx errors usually require (e.g.) five
days before a human sees them.
This allows for some overlap then.
But regardless, we're talking about a MAY here; and I'd be quite happy
with an implementation which returned the error intermittently -- so
long as the problem is brought to the attention of a human being capable
of fixing it, we've done all we should.
(Of course, programming this sort of intermittent response to cause
human action is rather more difficult if we must return a 4xx...)
If it requires human intervention, then you would be correct. Is this
sure to be the case?
No doubt it's possible to configure a overlap case; but it would require
at a minimum different TTls. This seems rare...
--
John Leslie <john(_at_)jlc(_dot_)net>