On Wed, 2006-12-06 at 11:02 +0000, Chris Lightfoot wrote:
> no, it's a temporary error, because a future attempt with
> the same sender/receiver/data stands a reasonable chance
> of success without there being any oeprator intervention
> -- see the description in the RFC.
No remote user, operator, admin etc in their right mind can make the
assumption that an over-quota condition will be fixed without operator
invention. Only the administrator, operator or user of the system
creating the 5xx error can, and only then given some level of
interaction with the system.
A remote MTA can only make the assumption that a retry will work, or
won't. That's not what I call a reasonable chance. To quote the section
of RFC2821 in its' entirety (giving additional context):
4yz Transient Negative Completion reply
The command was not accepted, and the requested action did not
occur. However, the error condition is temporary and the action
may be requested again. The sender should return to the beginning
of the command sequence (if any). It is difficult to assign a
meaning to "transient" when two different sites (receiver- and
sender-SMTP agents) must agree on the interpretation. Each reply
in this category might have a different time value, but the SMTP
client is encouraged to try again. A rule of thumb to determine
whether a reply fits into the 4yz or the 5yz category (see below)
is that replies are 4yz if they can be successful if repeated
without any change in command form or in properties of the sender
or receiver (that is, the command is repeated identically and the
receiver does not put up a new implementation.)
Note the particular attention paid there to the difference in
interpretation of the term "transient" between the sending and receiving
MTA.
I suspect that given the openness of this section of 2821, we'll have to
agree to disagree here. In my opinion, a long-term over-quota condition,
although rectifiable by user or administrative intervention, becomes
permanent according to the policy of the system in question. If you
choose to leave all quota-related problems as 4xx errors, you will
likely end up with a great deal of clutter in your queues.
Graeme
