Skippy:
Thanks for you explanation of milter-ahead! I had never quite gotten my head around that particular milter until I read your email.
Jeff G.
[EMAIL PROTECTED] wrote:
Even without seeing the headers, its a pretty common thing for spammers to send their spam through secondary mail servers. From the volume of this that I've seen I assume that a fairly large percentage of the spam software does this automatically.
The problem for the mail admin is of course that in a standard setup, the secondary has no idea what accounts are on the primary and so blindly accepts everything for the domain.
In sendmail its possible to set up a mail filter that accepts the spam connection and holds it open while it queries the primary to see if its a valid address. If it isn't the secondary refuses the spam right then and never queues it. The package I've used for that is milter-ahead from www.milter.org. I don't know if a similar setup is possible with postfix.
Skippy
Any chance you could post the headers of this email so that we could get a better idea of what happened?
Jeff G.
Michael Hrivnak wrote:
I have a question that relates directly to a spamming experience I just had.
I understand what an MX record is. I have setup multiple machines that will relay for my domain in the event my primary mail server is down. I did so by adding to those machines this in /etc/postfix/main.cf
relay_domains = $mydestination mydomaincom
All machines involved run Mandrake 10.0 or 10.1. That tends to work, but I found a problem. In theory, anyone on the internet can use these backup servers to send email to my domain. Someone could spam my domain all day and all night through those servers. In fact, tonight I received a spam email that came through one of those servers and even claimed to be from two accounts (which don't actually exist) on that backup server (why would an email be from 2 accounts anyway?). What can I do to prevent this?
Thanks a lot,
Michael
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