[Mimedefang] Hot do I stop becoming a spam relay.

WBrown at e1b.org WBrown at e1b.org
Mon Mar 12 10:29:51 EST 2007

mimedefang-bounces at lists.roaringpenguin.com wrote on 03/11/2007 10:35:43 

> First of all my sendmail does not allow relaying, but I am now getting a 

> lot of e-mail where email is sent to an unknown local user and then 
> there is a BCC to some other location:
> for example:
>     From: spammer at domain.com
>     TO:    XXX at ourlocal.domain.com
>     Bcc:   someone at external.com

What are you currently doing with those external addresses?
> I guess the letter of the of the law I should deliver the e-mail, to the 

> external address, since typo 's do happen, but there must be away round 
> it. May be I could not deliver Bcc if the to address is invalid?

No.  You are perfectly free to respond with 550 unknown user to the "RCPT 
TO: someone at external.com" command.  It is up to the sending SMTP host to 
deliver the message to the right server for the recipient. The exception 
would be for user where your server is the designated relay for their MUA. 
 Access to that should be restricted by requiring authentication, or 
restricting it to internal IP addresses.

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