On 10/12/2014 2:11 PM, Brian wrote: > On Sun 12 Oct 2014 at 18:45:42 +0200, lee wrote: > >> Martin Read <zen75...@zen.co.uk> writes: >> >>> On 12/10/14 15:53, lee wrote: >>>> And when they are filtered, does the sender get a message telling him >>>> that their message hasn't been delivered? >>> >>> The requirement in RFC 2821 (the successor to RFC 821 which you've >>> recently been referring to) section 4.2.5 that a server which issues a >>> 2yz completion status after final dot must return appropriate >>> notification to the sender cannot be fulfilled is an unreasonable >>> demand in the modern era. >>> >>> If you wait for all filtering to complete before issuing a response to >>> final dot, your mail server is vulnerable to denial-of-service attacks >>> unless you undercook your filtering; if you issue a 2yz status before >>> filtering is complete, then send the notifications demanded by RFC >>> 2821 if the deferred filtering results in a rejection, your mail >>> server is now a public nuisance because of the amount of backscatter >>> it generates. >> >> All this is no reason to violate RFCs. > > No RFCs are being violated. > > The mail is accepted. What the recipient does with the mail after that > is outside the scope of an RFC. There is no obligation on the recipient > to inform the sender that he has ripped up the mail and junked it. > > Most mail which comes through my letterbox goes straight into the paper > recycling box. If I stood outside the front door and told the postperson > I didn't want it there would be something else involved. > >
And, in fact, more and more ISPs are just accepting and discarding emails to non-existent users because rejecting such email helps spammers (any non-rejected email must be a valid user). Jerry -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/543b2a5e.90...@attglobal.net
