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How do I look up an MX record with nslookup?

Some material is very old and may be incorrect today

© April 2015 Anthony Lawrence

Anonymous asks:

We have an application that sends out mail, but it isn't working right. It's sending local domain mail to the wrong server. I figure it must be getting the MX from local DNS, but how can I check that with nslookup?

I'd install Linux and use "dig" or "host", but I suppose that's asking a bit too much.

I couldn't remember how to use nslookup for that, so I invoked Google, which sent me to Using NSlookup.exe, which enlightened me with this less than ideal wisdom:

To look up different data types within the domain name space, use the set type or set q[uerytype] command at the command prompt. For example, to query for the mail exchanger data, type the following:

   C:\> nslookup
   Default Server:  ns1.domain.com
   Address:  10.0.0.1

   > set q=mx
   > mailhost
   Server:  ns1.domain.com
   Address:  10.0.0.1

   mailhost.domain.com     MX preference = 0, mail exchanger =
                           mailhost.domain.com
   mailhost.domain.com     internet address = 10.0.0.5

But that's not right. It's not wrong, but it assumes the user is trying to find out if a machine IS an MX, which is not what you want to know. For your question, you'd do:

   > set q=mx
   > domain-you-want-to-know-about

For example, if you wanted to know the MX for my domain, you'd type "aplawrence.com".

Leave it to Microsoft to give the least likely usage as their example!

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