Re: [Emailcore] Proposed ESMTP keyword RCPTLIMIT
Laura Atkins <[email protected]>
| Newsgroups | gmane.ietf.smtp |
|---|---|
| Message-ID | <[email protected]> |
> On 20 Apr 2021, at 01:09, Sam Varshavchik <[email protected]> wrote: > > George Schlossnagle writes: > > >> The common limits we see in the real world (in order of most common occurrence/impact) are: >> >> >> Messages per connection >> Recipients per message >> Simultaneous connections per sending IP (this would be my number one suggested add) > > This is surprising: that messages per connection is more commonly checked than everything else. > > I would expect that a receiving server would prefer reusing the same connection, to send consecutive messages, than have the sender establish a connection, send one message, then tear it down. > > A long time ago that was Qmail's well-known bad rep: its simplistic implementation, how it created a connection for every individual message. So, a dozen messages to the same domain resulted in dozens of concurrent connections, all to send one message and disconnect. > > 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. I don’t think a discussion about why or if it’s sensible will make any difference. The companies who are closing the connections after X number of messages (5, 10 and 20 are all used) are not likely to either defend their technical decisions to the IETF or change their behavior after a decade and at least one whole infrastructure rearchitecture. What we should be doing is figuring out how to make these limits more clear to senders. laura [1] In at least one case the decision maker passed away a few years ago. -- Having an Email Crisis? We can help! 800 823-9674 Laura Atkins Word to the Wise [email protected] (650) 437-0741 Email Delivery Blog: https://wordtothewise.com/blog _______________________________________________ ietf-smtp mailing list [email protected] https://www.ietf.org/mailman/listinfo/ietf-smtp