Hot do I stop becoming a spam relay.

Hi!
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: spammerdomain.com
    TO:    XXXourlocal.domain.com
    Bcc:   someoneexternal.com

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?

Any pointers....

Andrew
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On 11 Mar 2007 at 14:35, Andrew Watkins wrote:

> Hi!
> 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: spammerdomain.com
>     TO:    XXXourlocal.domain.com
>     Bcc:   someoneexternal.com
> 
> 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?

First, if there is a "Bcc:" header in the incoming
SMTP data, the  
server at the other end screwed up...the whole point of
"Bcc:" is that 
other recipients aren't supposed to know about it.

Second, sendmail doesn't deliver based on headers from SMTP
data...it 
delivers based on the "RCPT To:" command in the
SMTP transaction.  So, 
whatever might be in a "Bcc:" header isn't going
to do anything.

Now, if you have some program to deliver the e-mail locally
that looks 
at headers and creates a new e-mail message if there is a
"Bcc:" 
header, then that's the problem.

"sendmail -t" is an example of a command that does
this sort of header 
parsing.  It's really only used for initiation of sending
mail, and I 
think it's ignored when in daemon mode, but check to see if
you are 
starting your daemon with this flag, just in case.


--
Jeff Rife |  
          | http://www.nabs.net/Cartoons/OverTheHedge/AntiqueOS.gif 


_______________________________________________
NOTE: If there is a disclaimer or other legal boilerplate in
the above
message, it is NULL AND VOID.  You may ignore it.

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in.com
MIMEDefang mailing list MIMEDefanglists.roaringpenguin.com
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defang

mimedefang-bounceslists.roaringpenguin.com wrote on
03/11/2007 10:35:43 
AM:

> 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: spammerdomain.com
>     TO:    XXXourlocal.domain.com
>     Bcc:   someoneexternal.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: someoneexternal.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.
_______________________________________________
NOTE: If there is a disclaimer or other legal boilerplate in
the above
message, it is NULL AND VOID.  You may ignore it.

Visit http://www.mimedefang.org and http://www.roaringpengu
in.com
MIMEDefang mailing list MIMEDefanglists.roaringpenguin.com
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defang