At 11:38 AM 8/5/2008, Tony Finch wrote:
It says nothing about connections: you can send multiple copies of a
message down the same connection.
I've seen an implementation opening multiple simultaneous connections
to do that. It caused resource problems at the server end.
At 03:00 PM 8/5/2008, Hector Santos wrote:
IMV, it depends on the client, is it a MUA client? an backend
server list distribution?
MUAs fall under SUBMIT and do not use the same retry strategy as SMTP clients.
In fact, I believe some MUAs will not even continue with the DATA
until all same session RCPT are positively resolved. I have to
double check if this was because of 5yx responses only, but under
ThunderBird if I tried to send to my server which checks for local
valid recipients, an address among a few that is invalid, it will
not continue sending it until it is fixed or removed from the TO:,
CC:, BC: address list. I'll be interested to try this later by
forcing a 4yx response instead to see how the MUA will behave.
I expect MUAs to fail if there is any 4yz or 5yz response to a RCPT.
At 03:19 PM 8/5/2008, Hector Santos wrote:
In the end, I think it boils down to how an implementor would design
to satisfy the functional specs.
On the automated side:
Does it create 1 copy per recipient on the sender outbound queue?
The implementor also has to take into account recipient limits.
At 03:52 PM 8/5/2008, Hector Santos wrote:
True, but there is at least one MUA - TBIRD that behaves this way. I
have not used Outlook in a long time to recall if it had similar
behavior. I will lean to the side that it did because its quite
possible the latter designed TBIRD researched and borrowed the logic
or probably felt it would be easier design for this human usage to
make the correction than to try to behave like a real MTA with
redundant retries. Although, there is the design option it could
issue a prompt:
The difference between MUAs and SMTP client is that the former can
revert back to the user for input.
Regards,
-sm