[plug] Addresses still in archives.

[Craig Ringer]

Steve Boak wrote:
> On Mon, 18 Oct 2004 02:23 pm, Craig Ringer wrote:

> Did you actually mean accept and then discard the mail from the suspect 
> system

Nope

> or can you tell postfix to simply drop the connection and not accept 
> mail from them at all?

That's right. Postfix can be configured to reject the mail on the spot, 
much the same way as some mailservers do when a user is over quota. For 
example:

$ telnet mail.postnewspapers.com.au 25
Trying 202.72.149.28...
Connected to access.postnewspapers.com.au.
Escape character is '^]'.
220 mail.postnewspapers.com.au ESMTP Postfix
HELO www.postnewspapers.com.au
250 mail.postnewspapers.com.au
MAIL FROM: fred at kjshdfksjdfhskdhfskdhf.com
250 Ok
RCPT TO: squark at postnewspapers.com.au
450 <fred at kjshdfksjdfhskdhfskdhf.com>: Sender address rejected: Domain 
not found
QUIT
221 Bye
Connection closed by foreign host.
$ telnet mail.postnewspapers.com.au 25
Trying 202.72.149.28...
Connected to access.postnewspapers.com.au.
Escape character is '^]'.
220 mail.postnewspapers.com.au ESMTP Postfix
HELO localhost
250 mail.postnewspapers.com.au
MAIL FROM: nouser at postnewspapers.com.au
250 Ok
RCPT TO: nouser at postnewspapers.com.au
504 <localhost>: Helo command rejected: need fully-qualified hostname

Note that postfix doesn't reject the mail until after RCPT TO:, even if 
the error ocurred earlier. This is a workaround for buggy mail clients, 
but also means you have more information about the request before it's 
rejected.

You can also configure helpul error messages and change what error 
things are rejected with.

All of this is clearly documented in the (excellent) postfix 
documentation and expanded upon by some well written examples on the 
'net. Two useful resources:

Postfix configuration - UCE:
http://www.postfix.org/uce.html

The Postfix Anti-UCE guide:
http://jimsun.linxnet.com/misc/postfix-anti-UCE.txt

TFM:
http://www.postfix.org/documentation.html

--
Craig Ringer