Email related DNS records

The DNS (Domain Name Service) plays a critical role in email delivery. You need to create a set of DNS records to make sure that your email can be delivered and that email can be delivered to you as well.

The basic record to setup is the MX record, which tells the email servers which server(s) handle email for your domain.

This page will make a general overview of all the needed records, more details are presented in each configuration section later on.

Please note that you will need more that the records defined in this page for a domain to operate properly: this is only for email.

An MX record (mandatory) tells who manages emails for your domain. You can have more than one, to build a chain of backup servers, but that is outside the scope of this guide. I assume your MX record points to mail.mydomain.com.

Please note that this implies as well the existence of an A record for mail.mydomain.com.

Example:

mail.mydomain.com.    x.y.w.z	            1800 A
webmail.mydomain.com. mail.mydomain.com.    1800 CNAME
@	              10 mail.mydomain.com. 3600 MX

For SPF to work, you need to setup a proper TXT record like the following:

@	v=spf1 mx ra=postmaster -all 3600 TXT

The DKIM record contains the public part of your domain DKIM keys:

mydomain.com._domainkey. "v=DKIM1; k=rsa; p=<< mykey >>" 3600 TXT          

In the above example « mykey » is a very long random characters string.

The DMARC record is used to publish your domain DMARC strategy

_dmarc.mydomain.com. "v=DMARC1; p=reject; rua=mailto:postmaster@mydomain.com;" 3600 TXT
_smtp_tls.mydomain.com.	"""v=TLSRPTv1; rua=mailto:postmaster@mydomain.com"""	3600	TXT

The following set of SRV records facilitate mail clients to discover your IMAP and SMTP servers:

_imaps._tcp.mail.mydomain.com. 0 1 993 mail.mydomain.com. 3600 SRV
_submissions._tcp.mail.mydomain.com. 0 1 465 mail.mydomain.com. 3600 SRV
_imap._tcp.mail.mydomain.com. 0 1 143 mail.mydomain.com. 3600 SRV
_submission._tcp.mail.mydomain.com. 0 1 587 mail.mydomain.com. 3600 SRV