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Re: Proposal for Adjusted DATA Timeout

2008-05-26 19:59:18

At 07:58 -0400 on 05/23/2008, Hector Santos wrote about Proposal for Adjusted DATA Timeout:

Hi,

I am wondering if writing a I-D or BCP is worth the effort here and your comments are welcome.

Basically, with the advent of larger emails and the direction of mail sophisticated mail receivers performing DATA pre-response callouts to process the message before determining what the response code will be, there is a greater potential for client timeout issues, duplicate resends and messages and of course, wasteful bandwidths and overheads.
[SNIP]


One way to eliminate the duplicates if the SMTP server has accepted and sent the message but the MUA did not hang around to get the acceptance ACK (or did not send the QUIT) is to save the Message-ID of messages that the MUA did this for (I assume the retransmission will have the same MID. If/when it attempts reinjection, compare the supplied MID against the saved list and reject the attempt with a 5xx status code (and text saying "You submitted this already and I accepted and forwarded it"). You can prune the entry after a designated wait time or when the message is resubmitted (the latter possibly before the wait time expiration).