What are MX Records?
MX records are used by mail servers to determine where to deliver email for a domain. If no email is sent or received from a domain, then there is no reason to have MX records configured within the domain. MX records are ordered based on MX priority. The lowest priority MX record is the first destination for email. MX records should only map to A records in a domain (not CNAME records), or other external mail servers to the domain. If email is sent to a domain with no MX records, mail delivery will be attempted to the matching A record. For example, if the domain example.com had no MX records, mail would be delivered the A record for example.com (if it exists).
MX Record Fields
|A) Name||This field is typically left blank for MX records as email is delivered to email@example.com. If your organization has an email hierarchy such that addresses exist for firstname.lastname@example.org, then you would require MX records with a populated name field. It is important to note, the domain name is automatically appended to the “Name” field of the record.|
|B) TTL||The TTL (Time to Live) in seconds is the length of time the record will cache in resolving name servers and web browsers. The longer the TTL, then remote systems will lookup the DNS record less frequently. Your nameservers will also receive less query traffic since most queries are answered by resolving name servers. Conversely, the shorter the TTL the faster any changes you make to your DNS will propagate in servers that have cached data. However, your domain will receive more query traffic.
Records that are static and don’t change often should have TTL’s set between 1800 (being on the low end) to 86400 seconds (30 minutes to 1 day cache).
Records configured with Failover or that change often should have TTL’s set anywhere from 180 to 600 (3 to 10 minutes cache).
If a change is needed for a record with a high TTL, then the TTL can be lowered prior to making the change and then raised back up again after the changes were made.
|C) Server||The mail server that will accept mail for the host that is specified in the name field. Your domain name is automatically appended to your value if it does not end it a dot.|
|D) Level||The MX level determines the order (by priority) that remote mail servers will attempt to deliver email. These will be delivered to the domain’s email servers defined in the MX records. The mail server with the lowest MX level will be the first priority.
All email would be delivered to mx1.mailserver.com only. If mx1.mailserver.com is offline or not accepting email, then mail would be delivered to mx2.mailserver.com. If mx2.mailserver.com is offline or not accepting email, mail would be delivered to mx3.mailserver.com. Mail would be delivered to mx1.mailserver.com again once it is back online. If multiple MX records exist with the same MX level, then email is set up in a round robin configuration, which alternates delivery between the servers.
|E) Notes||Add a helpful note with keywords so you can search for your records later.|
|F) Save||Save your record changes and don’t forget to commit your changes after you’re done making record changes for this domain!|
Video Tutorial: How to Add, Edit, and Delete Records
ADD AN MX RECORD
4. In this screen, you will add the record information. Follow the steps below:
A) Name: Enter a name for the record. Please note, in most cases the name field of the record is left blank for MX records.
B) TTL: Edit the TTL. Time to Live is measured in seconds and is the amount of time the record will cache in resolving name servers and web browsers.
C) Server: Enter the destination mail server for the domain.
E) Note: Add a helpful note with keywords so you can search for your records later.
F) Save and Close: Save your changes. Don’t forget to commit your changes.
Information on the NX Domain feature can be found in the Disabling a Record tutorial.
NOTE: If you point to an A record within the same domain, then mail for example.com will be delivered to mail.example.com. The tool tip at the top of the record configuration screen will display how the host will resolve:
If you point to a value external to the domain, then mail for example.com will be delivered to mx.mailserver.com. Please note, the value field must end in a dot (.) in order to keep the example.com domain from being appended to the end of the value. The tool tip at the top of the record configuration screen will display how the host will resolve.
EDIT AN MX RECORD
3. Under the MX Records section, select a record by clicking the check mark next to it, then click the icon to edit a record.
Please note, you can not edit a record that has not been committed following its creation.
DELETE AN MX RECORD
3. Under the MX Records section select a record by clicking the check mark next to it, click the icon to delete a record.
Please note, you can not delete a record that has not been committed following its creation.
4. The record will now show as strike through text, and is now in the queue of changes to be committed.