[nflug] Forged mail header bounces up exponentially

[D. Joe]

On Mon, Apr 28, 2008 at 07:20:34PM -0400, Robert Wolfe wrote:
> By specifying the IPs in the '$my_networks' variable that you would like
> to access your MTA.  I had a problem about NOT being able to send email
> off networking on my Postfix box (before it died a horrible death due to
> hardware failure) and just added the IPs that I will be connecting from
> with a mail client and it let me right on.  You can do the same (or at
> least should be able to do the same) to prevent off-network IPs from
> accessing your MTA.

I suspect that you are confusing what this thread describes, mailers
forwarding spam to addresses listed in either the From: header or the
envelope sender address of an incoming spam, with the operation of an open
relay.

If you are operating an open relay, your address will be listed as such in
the various black hole lists and it will be difficult to find other SMTP
servers that will accept mail from you.  But, in this case, the spam really
will be coming from your mail server, so rejected messages really should be
going back to you, if ever it even gets that far.

In what we are seeing now, the third party running an MTA most likely has
had nothing whatsoever to do with sending the original spam, and so only
becomes involved when these irresponsible forwarded messages are generated.  

It would be better that these spams were dropped, rather than forwarded.

-- 
D. Joe