I agree the RFC's still require it. I agree that an MTA can reject with a 5xx if it does not like the message. But, to say that a system that accepts all incoming email and filters at a later stage is required to send bounce messages on all the rejected email later is making a bad problem worse.
I am a perfect example of that. I reject at the MTA for RBLs. But accept pretty much everything else for later scanning on a much faster computer. I could send 30-40 thousand bounce messages a day, to people that did not actually send the emails. But instead I just throw them away. Requiring the internet connected MTA to do all the filtering is not practical for everyone, or even for most people. I am reasonable sure yahoo for one will queue up incoming email for later processing when the loads are high (new spam blast going on). For them to then send bounce messages for all the queued messages would flood many other servers. And I am sure that yahoo is not the only one that has an incoming volume great enough to only perform the fast checks on accepting the email and then do the more intense filtering later. Keep in mind that most of the email received by internet connected MTA's is spam. Numbers vary but I don't remember seeing a number under 50% for many years and for my own servers it is 500 good to 20-60 thousand spam. It is not practical to try and filter all of them at the MTA connection time. Phillip From: Francesco Vertova Sent: Fri 3/21/2008 1:43 PM To: [email protected] Subject: [xmail] Re: hotmail delivery problems At 19.16 21/03/08, Phillip R. Shaw wrote: > >>if a MTA accepts a message for delivery, it must either deliver or bounce.. >While this was a nice idea at one time, it really isn't desirable any more.. > >Why? SPAM. I get thousands of emails that I accept but are then >rejected by my spam filtering. You don't want me sending all those >bounce messages to your users (whose email address was forged in the email). If a MTA thinks an incoming mail is spam, it can reject it with a 5xx. If it doesn't - i.e., accepts it for delivery - then it must deliver or bounce (indeed, I think it's required to do that by relevant RFCs). >I would assume that hotmail (and the others) have user options that >say 'delete spam', so they don't have to look at it in their spam >folder. This could the reason that it goes into hotmail, and the >user never sees it. Some filtering is done when the email arrives, >but a lot of time more filtering is done later. Yes, I think what is happening is that hotmail or others mark the mail as spam and place it somewhere, users don't realize it and say "I didn't receive it". Actually it is delivered, and users can read it if they like and know how. Ciao, Francesco - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED]
