whatsmydns.net - DNS Propagation Checker
Waiting for lookup request...

MX Record Lookup

The MX Record Lookup tool is an online tool that lets you query DNS servers and get instant results.

Mail Exchanger or MX lookups are used to determine the MX records associated with a domain.

Looking for easier to understand results? Use the Global DNS Checker tool.

DNS MX Record

MX records, known as Mail Exchanger records, are used to identify which server should be used when sending emails to an address at the domain that the records are for.

Example MX record

An example MX record may look like the following:

Record Type Priority Value TTL
example.com MX 10 mail1.example.com 3600

example.com represents the domain of the record.

MX is the record type.

10 is the priority of the record. The lower the value, the higher the priority.

mail1.example.com is the value of the record. This is the address of the server which should handle email for this domain.

3600 is the TTL (time to live) of the record in seconds, this example represents 1 hour. This means that when a record has had updates made to it, then it will take 1 hour to update.

Multiple MX records

In many cases multiple MX records are added to a domain name, this allows for primary and secondary (backup) mail servers as well as a form of load balancing.

Lower priority records are always tried first when attempting to deliver mail. In the case that the mail server specified in the record with the lower value returns an error when attempting to deliver mail, the next highest priority MX record will be used. If multiple records have the same priority, then one will be chosen at random as a means to spread the load over multiple email servers.

Backup MX records

Backup MX records allow you to set a priority of which mail server should try and process the email first.

The lower the value, the higher the priority.

Record Type Priority Value TTL
example.com MX 10 mail1.example.com 3600
example.com MX 20 mail2.example.com 3600

In this example, the mail server at mail1.example.com will try to handle processing the email first.

Load balanced MX records

Multiple MX records with the same priority value allow you to have multiple mail servers processing email where one is picked at random. This is useful for spreading the load across many servers or network devices where a single server may not have the capacity to handle all emails at once.

Record Type Priority Value TTL
example.com MX 10 mail1.example.com 3600
example.com MX 10 mail2.example.com 3600

In this example, one of the two mail servers will get a chance to handle processing the emails equally.

Load balanced and backup MX records

A combination of backup and load balanced email servers can also be achieved with additional MX records.

Record Type Priority Value TTL
example.com MX 10 mail1.example.com 3600
example.com MX 10 mail2.example.com 3600
example.com MX 20 mail3.example.com 3600

In this example, the mail servers mail1.example.com and mail2.example.com will get a chance to handle processing the emails equally. If they fail to respond, then the mail server at mail3.example.com will try to handle processing the email.

How do you check MX records with a DNS lookup?

When checking MX records, you have many options available. The easiest option is to use an online MX checker tool like the one on this page.

If you would prefer to perform a MX lookup from your own local device, then there are a variety of tools to do so but the tools available will depend on your operating system. There are pros and cons when deciding to check MX records online vs on your local machine, depending on your use case you should consider which option is best for you.

Reasons to check MX records online:

  • Easy for anybody to do
  • Works in any web browser
  • Results are easier to read
  • You can more easily share results with others

Reasons to check MX records locally:

  • Results represent what you are experiencing locally
  • More powerful options available for advanced users

Checking MX records online

Using the online MX lookup tool is easy, all you need to do is enter the MX record into the search input and press search to run the MX DNS lookup request.

Additionally, you can also choose alternative DNS servers to perform the request with from the options available.

The online tool will perform the search, parse the results, and highlight the important parts of the results which can often be hard to read from the output that some of the command-line tools provide.

Checking MX records on Windows

The nslookup tool on Windows based systems including Windows 7/8/10/11 & Windows Server allows you to run DNS lookups for MX records using your systems local resolver by default, but also allows you to specify any DNS server you like.

Using the nslookup command

Using the locally configured resolver:

nslookup
> set q=mx
> example.com

Using a specific resolver:

nslookup
> set q=mx
> server 1.1.1.1
> example.com

Checking MX records on Linux and Mac

You have a few options when checking MX records on Linux and Mac. This includes MacOS and Mac OS X, as well as popular Linux distributions like Ubuntu, Debian, CentOS & Red Hat.

Using either the simple host tool, or the popular and powerful dig tool, you can perform MX lookup requests locally.

Using the host command

Using the locally configured resolver:

host -t mx example.com

Using a specific resolver:

host -t mx example.com 1.1.1.1

Using the dig command

Using the locally configured resolver:

dig mx example.com

Using a specific resolver:

dig mx example.com @1.1.1.1