Re: Protecting an Exchange server?

[Ned Fleming <ned () kaw us>]

On Thu, 13 May 2004 10:51:56 -0700, "Mark G. Spencer"
<mspencer () evidentdata com> wrote:

> I'm wondering if there is any way to locate an Exchange server on my
> internal network and place some kind of email appliance on our DMZ to
> actually send and receive email to the world and to the Exchange server on
> my internal network?

Windows only? Sure, there's no doubt $$$ something.

If you're willing to dip your toe into open source, I recommend
postfix running on FreeBSD (or on Linux). Total cost: the price of the
PC -- and the time you spend installing and configuring it, which may
not be insubstantial. It's not overwhelming (I did it), but if you've
never administered Linux or FreeBSD, well, you might want to start
elsewhere.

        http://www.linuxjournal.com/article.php?sid=4241

It's not an appliance, per se, but pretty close.

> Basically, I don't want my Exchange server to be accessible to the world in
> any way.

Excellent idea.

> So ..
>
> Internet -> My Email Appliance -> Firewall -> Exchange Server
>
> I envision setting up a dedicated route in the firewall between the email
> appliance out on the Internet and my Exchange server behind the firewall on
> my local network?

You won't set up a route. Instead, you'll point your DNS MX record to
the box on the DMZ. Then you'll set up a transport map on the DMZ box
that points to your internal Exchange box. Note: "transport map" is
the terminology postfix uses; you might see it listed as a
"smarthost." You'll also point your Exchange box to the DMZ box as its
"smarthost."

> Are there any email appliances that can work with Exchange in this way?
> It's my (limited) understanding that Exchange server can't "pop" to another
> email server to pull each Exchange users email, so I'm not sure exactly how
> or if my plan could be put into action.

Hmmm. Are you wanting to make your users' email accounts available to
them outside your network? If so, that's a separate story.



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