Definition
💡 Email blacklisting is the process of denying access to an IP address, domain, or email address due to excessive spam or a severely damaged sender reputation.
Common service providers like Google and Microsoft use blacklists to identify addresses and domains to prevent them from entering their servers as well as bothering their email users. If messages make their way to the recipients, they’re normally sent directly to the spam folder.
Example
If you’re in the marketing business and find that the mass emails you send are ending up in recipients’ spam or junk folders automatically, it could be because you’ve been blacklisted.
Several prominent blacklists, sometimes called blocklists, include The Spamhaus Project, SpamCop, and SURBL.
Why can an email be blacklisted?
Along with sending excessive spam, there can be other reasons that an email can be blacklisted.
- Email spoofing: Messages sent with a fake sender address.
- Countless outbound emails: A sudden increase in the number of outgoing messages sent.
- Complaints: Emails that are reported as spam and/or are then immediately deleted.
Additionally, an email account that has been hacked or a distribution list that contains illegitimate addresses can cause email blacklisting.
How to check the email for blacklisting
The simplest way to see if an email address, IP address, or domain appears on a blacklist is to use an online blacklist checker. You’ll find both free and paid tools that accomplish this task.
One to consider is MXToolBox which lets you check one address or domain per week for free. If you want to perform additional lookups or use advanced features, you can review the paid plans.
