Todd Lyons wrote: > What about an (further) enhancement to esmtp to allow rejection of > individual recipients at smtp data time? Yeah, it adds increased > complexity on both the sending and receiving sides, but it solves the > problem nicely of "deliver oversized msg to everybody except $ISP". > For the sender, it already has the ability to handle queued delivery > of an email to one out of the entire list of recipients, so it's not > like it isn't already capable of that aspect. As far as the receiver, > it just needs to be able to say 4xx for a specific user (and the > sender needs to understand it of course). > > Am I being too simplistic thinking that the addition of a new verb > could solve the per-user preferences problem nicely? > > Regards.... Todd
General problem, not just size, but spam threholds, et al. The protocol would need to change, as - at present - there are no 'handshakes' nor advertising of same, for the participating machines to even communicate a 'wish' to reject some, but not all recipients for a given message. http://www.courier-mta.org/draft-varshavchik-exdata-smtpext.txt Sam wrote the predecessor of that over ten years ago, and further actually included it into courier-mta, so if/as/when two of his MTA communicate, they can actually do this already. He was not the only such 'pilgrim', and 'Exim's own' Tony Finch also made a stab at what would be needed. Info on both can be found online. Ironically, local mail transport DID find accpetance, and DOES do exactly what is wanted - BUT -specifically is fenced-off from being integrated with smtp on that score or even presented as a public-facing service per se. So ... until *at least* one other MTA besides courier-mta actually implements EXDATA or the like so as to start building risk/reward, cost/benefit experience in real-world use .. OR lmtp *is* integrated into smtp ...nothing is likely to happen. 'Some folks' do take the BFBI exit and set their MTA to accept only one recipient at a time .. but that is not in accordance with the RFC, ergo 'not recommended'. Bill > > On Wed, Jan 19, 2011 at 12:34 PM, Dean Brooks<[email protected]> wrote: >> On Wed, Jan 19, 2011 at 08:16:35PM +0200, Stuart Gall wrote: >> >>> Ideally I would like to set a size limit for the yahoo.com domain so >>> that I immediately reject any mail> 5M with a yahoo recipient (and >>> possibly others throwing the baby out with the bath water etc) >>> >>> Is there a more sensible way to do this, or a better way all >>> together to deal with the problem. >> >> The difficult part in doing this with ACLs is that you wont often know >> the message size until SMTP DATA time, but by then your only choice >> would be to reject the entire message even if it meant rejecting all >> the other non-yahoo recipients. >> >> In my opinion, a better alternative might be to use a router to handle >> this. This has the positive side effect of automatically meshing with >> normal RCPT verification in the event that the SIZE attribute was >> given in the MAIL command, not throwing out all the recipients because >> of one Yahoo recipient, and being easy to read without the use of >> extra variables. >> >> Something like this right before your remote_smtp router: >> >> limit_size: >> driver = redirect >> domains = yahoo.com >> condition = ${if>{$message_size}{5M}} >> allow_fail >> data = :fail: message too large >> fail_verify >> >> The only other side effect I can think of is that it will generate a >> bounce instead of an immediate rejection at SMTP time (if SIZE isn't >> given in the MAIL command and thus caught by RCPT verification). >> >> This isn't a bad thing though since this would only apply to your >> authenticated relay users and you generally dont want to do SMTP-time >> rejection to mail clients. Some clients like Outlook will simply >> retry delivery over and over from the outbox when it gets an SMTP >> rejection. >> >> -- >> Dean Brooks >> [email protected] >> >> -- >> ## List details at http://lists.exim.org/mailman/listinfo/exim-users >> ## Exim details at http://www.exim.org/ >> ## Please use the Wiki with this list - http://wiki.exim.org/ >> > > > -- ## List details at http://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
