Re: [Emailcore] Proposed ESMTP keyword RCPTLIMIT
Richard Clayton <[email protected]>
| Newsgroups | gmane.ietf.smtp |
|---|---|
| Message-ID | <[email protected]> |
In message <[email protected]>, Laura Atkins <[email protected]> writes >> I see nothing to gain from forcing a sending server to artificially limit >itself; how after every N sent messages it has to close its socket, and >reconnect again. What is that supposed to accomplish? I don't get it. > >It’s a limit that was implemented more than a decade ago by some of the highest >volume receivers around. I don’t think we have to understand why they did it - >if even the folks who made the decision are still around. [1] We can just say: >this is commonly occurring behavior and it makes sense for SMTP to document it >and have a way to explain it. As you will know, the highest volume receivers have complex machine learning systems which can -- after a number of messages -- come to the conclusion that sending a SYN-ACK at the start was somewhat of a mistake... use of resources is more efficient if you make such senders (which dominate) start at the beginning again and you just refuse to let them connect "ever again". >From an engineering standpoint the overhead of 5xx-ing a small number of emails per session once the sender is understood to be bad may be a reasonable tradeoff compared with the complexity of chasing round all of your servers (of which you have rather more than one or two) identifying which open connections should be aborted. Other (related) considerations apply to email submitted over authenticated connections (you may realise as the email piles up that it is likely that the credentials are being misused) >What we should be doing is figuring out how to make these limits more clear to >senders. as I observed before -- don't expect much more than a generic statement (which comes down to "sending N good emails is the most you can expect to be able to manage") from such systems. Anything which revealed the current view ("actually, you've pretty much exhausted our patience") just is not going to happen (IMO) -- richard Richard Clayton Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety. Benjamin Franklin 11 Nov 1755 _______________________________________________ ietf-smtp mailing list [email protected] https://www.ietf.org/mailman/listinfo/ietf-smtp