I would like to setup email authentication for my company Exchange server. Since this is production I don't want to break something. I want to test this first in virtual machines and when I am sure it works fine, I can then deploy it on the production server.

I have a VirtualBox (windows server 2016) with Exchange 2016 installed. Can I deploy my spf, dkim and dmarc on this Windows so that I am confident that every thing works properly before going to prod?

Does my idea make sense (I new in this technologies)?

  • What do you want to test? The sending or receiving? Who is doing the authenticating in your virtual environment? Do you have DNS set up in the virtual environment? Or are you setting up a 2nd externally-facing email server using the VM (which would make it not a 'closed environment')? – schroeder Sep 4 '17 at 10:05
  • For sending, are you aware that SPF and DMARC are set via DNS and not on the server? – schroeder Sep 4 '17 at 10:13

For testing your DMARC for your own domain, there is no need to deploy in a test environment. It comes with a built-in pre-prod testing function.

Set your config to:
p=none pct=100 and set up the reporting emails to review for a month. This has 0 impact on the receipt of emails from your domain, but you get error reports.

Then, once you have fixed the various issues:
p=quarantine pct=10

This sets the policy to quarantine but only for 10% of the emails each receiver gets (the rest are p=none). As you get error reports (and user feedback), you slowly increase the pct to 100, then switch to

p=reject pct=10

and slowly ramp that up.

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  • Thanks for your answer. I think I am going to make tests on my prod server. after some search on how to setup, seems like Exchange don't support natively DKIM and a third-party must be installed to setup dkim. Do you have any tutorial to start with? thanks. – dmx Sep 4 '17 at 12:49
  • Exchange requires 3rd party support for DKIM. They recommend an email gateway that can handle that. Many to choose from. – schroeder Sep 4 '17 at 13:10
  • Since I know none of them, just give one to start with, please. – dmx Sep 4 '17 at 13:14
  • This is not a place to recommend products and services. – schroeder Sep 4 '17 at 13:15

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