How to Use Nslookup to Verify MX record configuration
You can use the Nslookup tool to verify that your MX records are configured correctly by querying an external or Internet DNS server.
Before You Begin
Before you perform the procedure in this topic, read Verifying DNS Design and Configuration.
How to use Nslookup to verify MX record configuration
At a command prompt, type nslookup, and then press ENTER.
Type server <IP address>, where IP address is the IP address of your external DNS server, and then press ENTER.
Type set q=MX, and then press ENTER.
Type <domain name>, where domain name is the name of your domain, and then press ENTER. The MX record for the domain you entered should be displayed. If the MX record is not displayed, DNS is not configured properly.
The example below shows how MX records appear for the fictitious domain, example.com.
Default Server: pdc.corp.example.com
> server 172.31.01.01
Default Server: dns1.example.com
> set q=mx
example.com MX preference = 10, mail exchanger = mail1.example.com
example.com MX preference = 10, mail exchanger = mail2.example.com
example.com MX preference = 10, mail exchanger = mail3.example.com
example.com MX preference = 10, mail exchanger = mail4.example.com
example.com MX preference = 10, mail exchanger = mail5.example.com
mail1.example.com internet address = 172.31.31.01
mail2.example.com internet address = 172.31.31.02
mail3.example.com internet address = 172.31.31.03
mail4.example.com internet address = 172.31.31.04
mail5.example.com internet address = 172.31.31.05
In this example, the preconfigured DNS server is behind a proxy server. Therefore, an external or Internet DNS server with a known IP address of 172.31.01.01 was used to perform the query. Next, the query type was set to MX to locate the mail exchangers for example.com. In this example, five SMTP servers are equally balanced, each with its own IP address. However, your domain might only have a single entry, as seen in the following example:
contoso.com MX preference = 10, mail exchanger = mailbox.contoso.com
mailbox.contoso.com internet address = 10.57.22.3