Knowledge Base

Best practices for sending outgoing mail from a Plesk server

Question

How to set up a mail server in Plesk to successfully send emails to external mail services?

Answer

Note: These instruction are applicable to Plesk servers with a local mail server installed.

1. Configure the hostname for a Plesk server

Go to Tools & Settings > Server Settings and type in your server's hostname:

Note: In Plesk for Windows Server with MailEnable installed, set up the hostname in MailEnable Management Console as well.

2. Enable SPF/DKIM/DMARC features

- SPF
  
  By default, a SPF DNS record is added to the domain's DNS zone during a domain creation, if this DNS record exists in the Plesk DNS Template.
  
  Make sure there is a TXT record for SPF in domain's DNS settings at Domains > example.com > DNS Settings:
  
  To learn more about SPF, visit this KB article.
- DMARC
  
  Note: By default, a DMARC DNS record is added to the domain's DNS zone during a domain creation, if this DNS record exists in the Plesk DNS Template.
  
  Make sure there is a TXT record for DMARC in domain's DNS settings at Domains > example.com > DNS Settings::
  
  To learn more about DMARC, visit its overview page.
- DKIM
  
  Make sure that DKIM support is enabled server-wide in Plesk at Tools & Settings > Mail Server Settings:
  
  Make sure that DKIM support is enabled for a domain at Domains > example.com > Mail Settings:
  
  To enable this option for all domains in Plesk, visit these KB articles:
  - enabling DKIM signing for all domains in Plesk for Linux
  - enabling DKIM signing for all domains in Plesk for Windows Server
  Finally, verify that TXT records for DKIM are present in domain's DNS settings:
  
  To learn more about DKIM, SPF, and DMARC Protection, visit this Plesk documentation page.
  
  Note: In case of multiple DKIM keys are configured, verify that they are set on different selectors (default._domainkey.example.com, new._domainkey.example.com, etc.)
  
  Use online checkers, like MXToolBox and www.mail-tester.com, to verify that email validation features are configured for the domain: SPF, DMARC, DKIM.

3. Create a reverse DNS

A reverse DNS (rDNS) lookup returns the hostname of an IP address. Many mailbox providers, including Gmail and Yahoo!, will block email coming from a mail server that does not have rDNS in place.

To configure rDNS, a PTR DNS record should be created by the owner of the IP address. Contact your hosting service provider or Internet Service Provider (ISP) to get more details.

If Plesk is installed on a cloud server, visit this KB article.