Hi everyone,
I'm considering a dual imgate setup as our primary means of defending
against spam.
How does imgate know about the email accounts that exist on the mail server
so that Imgate is able to reject email sent to non-existent accounts? Do
you run a script daily that updates imgate with all of the mail server
account info?
Another thing I am confused about, with the dual imgate configuration, is
how my mail users send their email using our smtp server. I think I may
understand the process. Perhaps you can tell me if my understanding is
correct or if I'm mistaken in my interpretation.
For every domain I host we would set up a DNS record such as:
somedomain.com. IN MX 10 IMGate1.ISPdomain.com.
somedomain.com. IN MX 20 IMGate2.ISPdomain.com.
That means all incoming email for somedomain.com will go to one of the
imgate/postfix mail servers (MTA) because of the presence of the MX records.
So far so good.
My users have their smtp mail server defined in their email client as
mail.somedomain.com. So apparently they find the A dns record for
mail.somedomain.com and the MX record is ignored (not part of the process
involved when they send email) which means they will connect directly to my
smtp server when the send email correct? Which is critical because we use
smtpauth. And spammers can't get sneaky and try to send email directly to
mail.somedomain.com, bypassing imgate, because that would be prevented due
to the fact that it's the mx record that controls what server they send to
(not the A record) and the MX record is pointing to imgate.
Is that a correct interpretation of the in-coming flow?
Now the web site also says, At each Imail machine and at each relayed
machine, you have the choice of which IMGate machine to use for outgoing
email.
In terms of the out-going email flow..
I'll only have one email server but I will have two imgate servers. I'm
also using smartermail not imail. So apparently when smartermail is going
to send email to external email servers it actually would do so by
forwarding email to one of the imgate servers? How do you configure that to
happen? Is that normally some kind of gateway setting in the email server?
How does this arrangement effect how other site's anti-spam checks work in
regard to accepting email from us? Is there a possibility that by
introducing the imgate servers, between our mail server and the recipient
mail server, might cause the recipient mail server to reject email from us?
Sorry about all the questions. Just trying to get my head around the
process before I move ahead with evaluating imgate.
Thanks for your help!
