howdy,

maybe rfc 2821 (ad smtp, successor to rfc 821) will put some light on 
this topic?

regards,

timo schoeler

> Hm,
>
> I tested with a 3 MB message with a "bad word" in the header. The mail 
> gets identified
> as "bad" immediately, but the transfer doesn't stop.
>
> Jan  4 23:50:20 server postfix/smtpd[16313]: connect from 
> mail.gmx.net[213.165.64.20]
> Jan  4 23:50:21 server postfix/smtpd[16313]: 3CA6F1E998C: 
> client=mail.gmx.net[213.165.64.20]
> Jan  4 23:50:25 server postfix/cleanup[16315]: 3CA6F1E998C: reject: 
> header Subject: online casino from mail.gmx.net[213.165.64.20]; 
> from=<florian.stoehr@gmx.net> to=<flo@wolfnode.de> proto=SMTP 
> helo=<mail.gmx.net>: Bah, go away!
> Jan  4 23:51:09 server postfix/smtpd[16313]: disconnect from 
> mail.gmx.net[213.165.64.20]
>
> :-(
>
> Bad, I thought it disconnects immediately when a header check matches.
>
> Florian