Getting your IP address blacklisted can have serious impacts on your email deliverability and even on your ability to operate a business online. If you receive a bounce message that says “Your IP address is blacklisted” or similar, it’s time to act.

A blacklist is a database that contains IP addresses that have been flagged for sending spam or other malicious activity. Cybersecurity companies create blacklists, and free mailbox providers and anti-spam vendors use them to protect their users from unwanted emails. Some companies also use blacklists to block access to websites and other services from servers that have been compromised by hackers.

How to Continuously Blacklist IP Addresses for Enhanced Security

Some blacklist IP addresses are manually created by security professionals, who look for patterns of behavior that indicate that a server is being attacked. For example, a server may be blacklisted if it is repeatedly sending requests for data at a high rate. This type of attack is called a denial-of-service attack, and it can cause legitimate users to experience slow Internet connections or errors when trying to request information from the server.

Other blacklists are automatically generated by real-time blacklist servers (RBLs). These servers collect blacklist data from multiple sources and distribute a compiled list to all subscribers. When a computer connected to an RBL receives a request from an IP address on the list, it immediately blocks the attacker.

Many blacklists have a self-service removal process that allows you to submit a request for your IP address to be removed from the list. The more open and cooperative you are when submitting a request, the easier it will be to get your IP address removed from the list.