Hi Andy,
You might have the problem of forged spam E-mails. Please refer to the following
article,
http://pobox.com/valid1.html
The mails don't use any relay but using the normal SMTP procedure instead ( a mail
server will return any mail back if the receiver of the mail is nonexistent ). You can
test it if you know how to send an E-mail via " telnet <mail server> 25" and the
only way I know to stop these mails is to block the IP addresses where the mails come
from ( of course, you may block some valid mails also.).
Hope it helps.
Michael
> 主題(Subject):
> SMTP Relay Security
> 寄信人(From):
> "Andy Kirk" <[EMAIL PROTECTED]>
> 日期:
> Fri, 10 Jan 2003 22:46:11 -0000
> 收信人(To):
> <[EMAIL PROTECTED]>
>
>I was until about an hour confident that my SMTP relay was secure. At that
>time, I received a spam email promoting 1,000,000 email address, that
>appears to have been sent from my mail server. At least, the From says
>[EMAIL PROTECTED], and from looking at the headers, the from address
>also contains a secondary email address from yahoo. The user portion of the
>email, is a random generated name that does not exist on my server.
>
>The question I have are :-
>
>1. Is it possible for someone to basically use my relay to send mail to my
>domain
>2. Is there anyway to test if this is possible
>3. Is there anyway to stop it, whilst still allowing email destined for my
>domain to be received.
>
>Regards
>
