Re: [Emailcore] Proposed ESMTP keyword RCPTLIMIT
Ned Freed <[email protected]>
| Newsgroups | gmane.ietf.smtp |
|---|---|
| Message-ID | <[email protected]> |
Interesting and good to know. Thanks. Ned > Generally speaking when I advise senders on their rate limits, I have them use > the smallest denominator possible, because most commercial MTAs will take a > per-hour rate limit and implement it as "send the hour's allotment in a single > burst and then wait 59 minutes", which I don't think most receivers want, so I > advise setting a per second limit when possible. One message per second is > better than 3600 messages per hour if it means a 3600 message burst and then a > long wait. > Mike > -----Original Message----- > From: ietf-smtp <[email protected]> On Behalf Of Ned Freed > Sent: Monday, April 19, 2021 7:34 PM > To: John R Levine <[email protected]> > Cc: Ned Freed <[email protected]>; [email protected] > Subject: Re: [ietf-smtp] [Emailcore] Proposed ESMTP keyword RCPTLIMIT > > On Mon, 19 Apr 2021, Ned Freed wrote: > > > I'm especially interested in people's thoughts on rate limits. The > > > problem I have with rate limits is, well, how to express them. ... > > A little surveying might be in order. > > I see that Postfix lets you set both the numerator and denominator of > > the rate limit, but the denominator defaults to a minute. It has > > separate rate limits for connections and messages. > > Exim also lets you set both, the examples use an hour. The > > documentation says that if you use a large interval that lets people send bursts. > Sounds familiar. Oracle Messaging Server lets you set both; the denominator default is one hour. > We store the limits in memcache or Redis so they can apply across mutiple MTAs. > The usual limit is per-IP, but we support per-host and per-domain as well. > The demoninator in PowerMTA is a string rather than a number, possible values are sec, s, min, m, hr, or h. It supports per-IP and per-host and probably other stuff; my familiarity here is limited. > I assume the Exim and Postfix limits are per-host, which in most cases translates to per-IP. > I have to say there's more consistency here than I expected. > Ned > _______________________________________________ > ietf-smtp mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/ietf-smtp > _______________________________________________ > ietf-smtp mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/ietf-smtp