DNS Settings for E-Mail

Postini Spam Filtering DNS Records

Postini provides our spam filtering services..  This is a hosted service with 2 data centers (primary and backup) for processing e-mail.  You will need to change your MX records to direct email destined for your domains through Posini's data centers.

Insert the following DNS MX records at a higher priority than your current DNS MX records for your domain. (This changes the preferred mail hosts for your domain to the servers of your new email protection service.) IN MX 100 IN MX 200 IN MX 300 IN MX 400

For example, your updated MX records should look similar to this: IN MX 100 IN MX 200 IN MX 300 IN MX 400 IN MX 500 (your old DNS MX entry) IN MX 600 (your old DNS MX entry)

Check your MX records


  • Important: The time for MX record changes to propagate is based on your TTL (time to live) setting. For example, if your TTL was originally set for 24 hours, you must wait the full 24 hours for the MX record changes to take effect.
  • Some DNS services don't allow prioritization using the numbers 100-600, and may use a different numbering scheme (for example, 1-6). You may use any prioritization numbers as long as the DNS MX entries are in the order described above.
  • You should delete your old lower priority MX records once you verify the email is flowing correctly through your new email protection service. (This prevents spammers from sending junk email using older DNS MX entries, thus bypassing your email protection service.)

After the MX changes have propagated, your next step is to test that your mail server can receive email from your new email protection service. This test must be successful before you can add users to your email protection service. Be sure to wait until your MX record changes take effect (after the length of your TTL), otherwise your MX record test will be unsuccessful.

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