Querying a domain for Mail (MX) Records

Last Modified

Wed Nov 30 21:40 GMT 2016

Description

This article will show you how to query for a domain's mail server. Sometimes this can be handy when attempting to resolve mail issues.

We'll use n-able.com as an example.

Environment

  • N-able N-central 6.x and higher.

Solution

  1. Click on Start, point to Run and type: cmd.exe and press <Enter>.
  2. Type: nslookup and press <Enter>.
  3. Type: set type=mx and press <Enter>.
  4. Type: n-able.com and press <Enter>.
  5. Here is what the results look like:
  6. Now, let's take a look at the results:

Each entry represents a mail server that is configured to accept e-mail for the n-able.com.com domain. Note that each entry has a unique FQDN at the end (i.e. n-able.com.s8b1.psmtp.com), and that each FQDN is lead by a number (i.e. 2,4,6,8). Those numbers tell you which server to send e-mail to first - they indicate the priority of the server.

Note: the lower the number, the higher the priority (i.e. you'd send the e-mail to the FQDN with a priority of 2 before you'd send it to the server with a priority of 4).

There are two common problems that can occur:
  1. Two unique FQDN's have the same priority:
  2. The priority given to the FQDN's are not consistent.

Whatever priority is going to be given to the MX records, they have to be consistent (i.e. 2,4,6,8 or 100,200,300,400 or 10,40,50,60). If they're not, it can cause all sorts of mail-type badness to occur.