At 13:34 7/08/02 -0700, Chris Wedgwood wrote:
On Sun, Aug 04, 2002 at 11:33:32PM +1200, Peter Mott
But the telecom delegated /23 had no name resolution.
Empty/broken zone, lame delegation or name-servers not responding?
For your original email is sounds very much like the latter, in which
case *most* things will keep working albeit a little more slowly at
Email won't be lost, it will remain in the queues, web-traffic should
be blisfully ignorant of this.
Sorry, I just don't understand why this was such a problem... reverse
is broken for so many people and they never notice it.
It depends *whose* reverse dns is broken....
MTA - MTA transfer of mail will normally get around the problem of broken
reverse DNS, usually just with a bit of delay in the delivery of the
message, and perhaps a lookup failure warning in the headers. This is
because MTA's usually have connection timeouts that are longer than dns
lookup failure timeouts.
However if the reverse DNS for end users (eg, dialup, Jetstream, and so
forth) is broken in such a way that the DNS times out instead of
immediately failing, this can pretty much kill email for those end users.
When the user connects to the mail server, most MTA's (Sendmail certainly
does) try to do a reverse lookup on the clients address. If that failed
immediately then there wouldn't be a big problem, but if the nature of the
dns failure means that every single lookup has to time out, (typically a
couple of minutes) then the mailserver wont respond with its welcome banner
until after that timeout.
Trouble is, most typical end user email software simply won't wait that
long before giving up, and even if it would, the user themselves usually
get impatient and cancel the attempt.
From the point of view of that end user their email
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