On Oct 31, 2011, at 8:55 AM, Tony Finch wrote:
Steve Atkins <steve(_at_)blighty(_dot_)com> wrote:
Mail that's delivered quickly, in a minute or so, vs mail that sometimes
takes a half hour to deliver makes a difference to the end user.
An ESMTP client, such as your ISP smarthost, will wait a while before
retrying in response to a 4xx deferral. The RFCs say they should wait at
least 30 minutes the first time.
Why not just ignore this suggestiona and retry more frequently?
Each delivery attempt consumes significant system resources, both at the
client and the server. It's also "unfair" behavior by the client, consuming
more server resources than better behaved clients in an attempt to get
mail delivered faster than that from other clients.
If, for example, the client was continually deferred and retried every
minute, rather than using a reasonable delay will consume 30 times
the resources over the first half hour compared to a well-behaved client.
Cheers,
Steve