If you’re an email administrator, chances are you’ve seen this in your error logs:
421 mx.fakemx.net Service Unavailable
What does it mean?
FakeMX is a free service that offers a mail server that does nothing other than reject connections all day. You can read more about the FakeMX service on FakeMX web site. According to the FakeMX site:
Many SPAM mails are sent to the lowest priority mail server in the hope that you have less anti-spam systems in place to deal with the mails, others may randomly pick an MX server to send to. Legitimate mail is normally sent to the highest priority mail server that is online, if mail to this server fails lower priority servers are generally tried in order.
What can I do?
If you’re seeing this error message in your logs, it could mean one of two things:
- Your mail server isn’t interpreting the priorities of recipient domain MX records correctly; or,
- One of your users tried to email a user at a domain for which no valid mail server is available.
If your mail server is broken, it’s likely you’re running a VERY out dated mail server. Check with your vendor. If on the other hand a user is sending email to a domain that doesn’t want to receive email, don’t panic. This probably won’t harm your IP reputation in any way.