What is the proper format of an MX Print

The proper format of an MX record often follows the example below:

If you telnet to port 25 of that IP using "telnet mail.yourdomain.com smtp" you should see 220 and then a hostname. If possible, use the hostname from the 220 greeting message rather than inventing a new mail.yourdomain.com name.

If you have a backup mailserver, you might use something like this:

MX records only affect mail delivery. They have no effect on HTTP, FTP, or any other protocol besides SMTP.

NOTES:

1. Never point mail.yourdomain.com using a CNAME. You should only use an A record for mail.yourdomain.com.
2. The MX number gives the "preference" assigned to that record; lower numbers are preferred. In the "backup mailserver" example above, the sender will try to access mail.yourdomain.com before it tries mail2.yourdomain.com, since the former uses a lower MX number (1) than the backup (2). 10 is a default value that many people use, but you may certainly use a different number.