DKIM (DomainKeys Identified Mail) provides a
method used to validate a domain name identity that is associated with a
message. It lets an organization to take responsibility for a sent
message by attaching an automatically generated digital signature to it
and uses cryptographic techniques to validate authorization for the
signature presence.
To provide the DKIM support, Plesk uses the functionality of an external
library (Linux) or of the mail server supplied with Plesk (Windows).
Warning: If you use an external DNS service, DKIM signing will work for
outgoing messages, but the receiving mail server will not be able to
validate these messages. As a workaround, you can switch off Plesk
DNS server and add a corresponding DKIM-related DNS record on the
external DNS service. In this case, the receiving server will be able
to validate the messages. Learn how to enable DKIM email signing for
domains that use an external DNS
server.
Enabling or disabling DKIM on the Server
DKIM is enabled in Plesk by default.
To disable DKIM or to keep it only for outgoing or incoming mail,
go to Tools & Settings > Mail Server Settings (under “Mail”),
scroll down to the “DKIM spam protection” section, and clear
one of the following checkboxes or both of them:
-
Allow signing outgoing mail. This option enables customers to
switch on the DKIM signing of outgoing mail on a per-domain basis. It
does not automatically enable signing of all outgoing email messages.
To use DKIM, users must switch it on for individual domains. -
Verify incoming mail (Plesk for Linux). This option switches on
DKIM checking for all incoming mail. All messages are checked, and if
the check fails, are marked with a special header.
Note: You cannot disable DKIM checking for incoming mail if
DMARC is enabled.
Enabling DKIM Email Signing for a Domain
If DKIM signing is enabled on the server (see the Enabling or
disabling DKIM on the Server section above), customers can sign
outgoing mail for their domains.
To enable DKIM signing of outgoing mail for an individual domain:
- Open the corresponding subscription for managing.
- Go to the Mail tab > Mail Settings.
- Select the domain and click Activate/Deactivate Services.
- Select Enable for DKIM spam protection system to sign outgoing
email messages and click OK.
Note: The DNS service must be activated on a domain.
After you have activated DKIM for a domain, Plesk adds the following two
records to the DNS zone of the domain:
-
default._domainkey.<example.com>- contains the public part of
the generated key. -
_ domainkey.<example.com>- contains the DKIM policy.