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Re: Protection against fake mails
From: "Mark Owen" <mr.markowen () gmail com>
Date: Wed, 9 Apr 2008 15:22:11 -0400

On Wed, Apr 9, 2008 at 12:37 PM, WALI <hkhasgiwale () gmail com> wrote:
 How do I guard against such emails originating from fake email
impersonations. Is there something I can do at our email gateway, proxy or
exchange sever (2003) levels?

Basic protection is to only allow e-mail originating from your domain
name to be allowed from a specific set of trusted mail servers.  This
will protect you internally from fake e-mails spoofing your domain but
will not block other spoofed domains.  Spoofed e-mails from other
domains may be blocked by relying on reverse DNS lookup and comparing
the resultant domain with that of the one specified in the e-mail, but
this will also block misconfigured servers and some sites on shared
hosting.  Long answer short, if you don't want to miss any e-mails
then theres really not much you can do.

What you can do to prove that your domain is not spoofed is to enable
DomainKeys[1] on your server.  If everyone did this then blocking fake
e-mails would be possible.

Hope this helps.

[1] http://en.wikipedia.org/wiki/DomainKeys

Mark Owen

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