On Fri, 8 Sep 2000, Dave C. wrote:
> Well, when you reject at SMTP-time, it is the sender MTA's
> responsibility to send the bounce. In the case of a legitimate email
> (with a mistyped address or something), the sender MTA will usuaully do
> so. In the case of a spam, we really don't care what it does ;)
True. But for legitimate mail, I want to send all of this:
Your message to ${LOCAL_PART}@??? has not been delivered, because
"${LOCAL_PART}" is not a known mailbox on this system.
User mailbox names normally consist of a sequence of letters followed by a
sequence of digits. The letters are (some of) the user's initials, the last one
being the first letter of the user's surname. The first digit is always greater
than 0. There are a few 4-letter names that contain no digits.
A common error is to confuse the digit "1" with the letter "l". For example,
Orlando Jacob Lassus' mailbox might be called ojl234, which sometimes gets
misread as oj1234. The digit "0" and the letter "o" can cause similar
confusion.
The web page
http://www.cam.ac.uk/CambUniv/Finding/ contains information about
finding people at Cambridge University. If you need further assistance, please
email to postmaster@???, giving as much information as possible.
That's far too much to put in an SMTP error message, but we have found
that it does reduce load on out postmasters - at least for those senders
that actually bother to read it (which is another problem again).
> Of course, it would be nice if all MTA's were smart enough to actually
> include the text after your 5xx code in the bounce message they
> generate ;)
That's also true.
> Of course, you could perhaps establish a list of 'legitimate' mail
> servers, and accept messages from those hosts, and send the bounce. Any
> others would get rejected at SMTP time..
That is *exactly* what I do do, but the set has to be pretty crudely
defined (e.g. I exclude all of .com) and also has to be maintained.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
