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daniel wrote: |
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> My boss wants me to create a bunch of mail relays to capture and relay mail |
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> sent to us and discard spam etc, but I'm not sure where to start. I'd like |
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> to use exim unless you all have a better idea. To be honest, at the moment, |
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> I'm not sure where to start. |
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> |
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> Here's a simple diagram that might help you understand what it is we want to |
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> do (fixed width font will help): |
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> |
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> [SMTP] [SMTP] [SMTP] [SMTP] |
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> | | | | |
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> +---------+----+---+---------+ |
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> | |
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> [SMTP+POP3] |
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> |
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> Each of the SMTP servers have different routeable IPs and are linked together |
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> via a RoundRobin DNS. Their sole purpose would be to check mail being sent |
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> to them against a list of known users @ourdomain.com and possibly filter spam |
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> as well. Messages that satisfy the filter would then be forwarded to the |
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> main mail server where we would all pick up our mail with our various email |
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> clients. |
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> |
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> So at the moment, my main issues are: |
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> |
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> - How do I replicate the user list from the master to the satellites? |
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> - What MTA should I use on the satellites and how would I configure it? |
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I am assuming (from the 4 smtp servers) that you have at least |
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several hundred users, who receive lots of email. That being |
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said, surely you must be using LDAP. As to the MTA, well pick |
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your poison. I'm a Sendmail guy, but that's just me. |
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My first thought is that your first line of defense should be |
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a bank of smtp servers that know nothing of your internal users. |
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The first line of defense should be focused on virus detection, |
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adherence to SMTP protocols and RFCs, greet-pause, listing |
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(black, white and grey) and my personal favorite, the tar-pit. |
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Only mail that gets past the first line of defense gets to a |
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SMTP server that knows or cares about user account names. |
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And another thing, if your company is as large as it should |
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be to justify 4 outside STMP servers, why would you be using |
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pop? Use IMAP (and probably Maildirs) so mail can be backed |
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up to tape and not scattered across hundreds of workstations. |
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Just my first thoughts, based on no actual knowledge of your |
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environment. |
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Best, |
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Ray |
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-- |
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