Already manage all your DNS records through your registrar? Perhaps you subscribe to a DNS service that uses multiple-location and/or anycast redundant DNS servers; understandable that you’d want to continue using this service! However it does make configuration of things like mail services and new subdomains a bit trickier.
When using your Plesk server for DNS management, all of the records are set up automatically for you, so there’s basically no technical configurations required — simply update name servers and you’re all set.
When using external DNS, there’s a few different types of records you need to configure for mail to work well. On the upside, you can always copy them from Plesk when creating them externally; the downside is that you’ll have a bunch of things to configure.
Rather than having to track down the right configurations, we strongly recommend simply copying the following records from Plesk to your external DNS provider.
MX (Mail eXchange) Records
These records point incoming mail to the correct server that’s configured to receive mail for the domain. If hosting mail within Plesk with Websavers, you only need to use one, but external providers like Google Apps uses multiple.
Note that, while they can be, these should not be configured to point to IP addresses directly, so you need to set up an A record that points to the right IP, then use the A record in the MX record.
Example MX Record: mail.yourdomain.com
(mail.yourdomain.com must also exist as an A record, see below!)
A records (or CNAME)
Sample A record: mail.yourdomain.com -> 127.0.0.1 [be sure to use the actual server IP here]
Sample CNAME record: webmail.yourdomain.com -> mail.yourdomain.com
The sample A record here is multi-purpose. You can use it in your mail applications to route IMAP/POP/SMTP connections to the right server, and you can use it in your MX record to route new incoming mail to the same server. You could opt to use it for everything, but most people tend to prefer sticking to a particular use for specific records to keep some semblance of organization to their DNS configurations.
The sample CNAME record is simple! It tells us that webmail.yourdomain.com is found at the same IP as mail.yourdomain.com. Yes, you could just use two A records, but with a CNAME, if you ever want to change the mail server IP, you only have to do so in one spot, assuming that incoming mail, IMAP, POP, SMTP and Webmail will reside on the same server.
(Usually just a record of type TXT): details on that here: https://en.wikipedia.org/wiki/Sender_Policy_Framework
Sample: v=spf1 a mx include:_spf.websavers.ca -all
Disable Unused Services
Be sure to disable any services you’re *not* using for the domain in Plesk.
If the DNS is external, turn off DNS for the domain. If a particular domain uses Google apps for email, make sure to disable mail for the domain as well.
Manual Record Creation
Don’t forget that by hosting your DNS externally, every time you add a subdomain in Plesk for hosting, you’ll need to manually create that A or CNAME record at your DNS host; this will not happen automatically.