On Fri September 2 2005 15:44, John C Klensin wrote:
I am reconstructing this from a fading set of memories, but, if
those memories are correct, Jon tried to make a distinction in
821, partially left over from its predecessors. I believe the
intent was to distinguish between:
"error": the client did something wrong that the server
detected. Syntax errors in commands, commands out of
sequence, invalid commands, and so on would be "errors".
"failure": the client behaved according to the
specifications, but the server was unable to deliver the
mail. "Mailbox not found" and all of the temporary
conditions such as "mailbox full" were, in that sense,
So, given this question, it seems to me that this should be
rationalized. It would be good if this list could reach a
conclusion as to whether I should try to find and remove the
remaining uses of "failure" or whether it would be worth it to
try to reestablish the original distinction. Of course, the
latter would require agreeing on what that distinction was: the
fact that Valdis reached a different conclusion than the one
above indicates to me that agreement might not be trivial.
I agree with the distinction and would like to see it reestablished.
But I don't see any conflict with Valdis' remarks; a client error
should elicit a 5xx response whereas a failure would result in a
4xx (temporary failure) or 5xx response (permanent error).