On 05/11/2011 04:35 PM, Michael Scheidell wrote: > if someone sends an email to 175 people, once they hit 'x' number in the > first email attempt, we send '4xx too many emails'
> ie: > ehlo *.yahoo.com > mail from: <some...@yahoo.com> > rcpt to: <one> > 250 ok > rcpt to: <two> > 250 ok > [skip to 100]. > rcpt to: <onehundered> > 4xx too many We do something similar, except that the maximum number of recipients per envelope we set at 1. The second and all subsequent get a 4yz error during RCPT. We perform this after greylisting, ie: ... RCPT TO:<fistrecip> 451 4.7.1 Greylisting in action RCPT TO:<secondrecip> 451 4.7.1 Greylisting in action ..some time later... RCPT TO:<firstrecip> 250 ok RCPT TO:<secondrecip> 451 4.7.1 One at a time please DATA ..after another retry.. RCPT TO:<secondrecip> 250 ok DATA Rationale being that content filtering during DATA can be customized on a per recipient basis, without having to generate bounces after the fact nor resorting to dropping emails silently. > RFC'S seem to indicate that they should send a data command next and > send the email to be delivered to the first 99, then try the next 51 on > the next highest mx. Or in our case, the first one, and retry for the next 149, get one more out, retry for the next 148, and so on. We do greylist, and Yahoo gets a rather long default greylisting and very short AWL. > doesn't happen on yahoo.com > they drop the connection, and try again at next highest mx, then on mx4, > bounce the email back to sender with the last mx's ip in the error > message and the 4xx too many Interesting. My experience has been that Yahoo does retry at the same MX but will not go to the next MX in response to 4yx errors. (OTOH if the connection times out they do go on the next MX) -- Joe Sniderman <joseph.snider...@thoroquel.org>
