IP Blacklist Check

Please enter IP to Check
	Example: 74.125.226.82

What is an IP DNS Blacklist?

IP blacklists are maintained lists of known or suspected spammers. This IP blacklist tool checks to see if your IP address is included on a public IP blacklist. Occasionally, legitimate websites or mail servers can be erroneously included into IP blacklists. This can cause your emails to be rejected when they are processed by the receiving SMTP server.

How IP Blacklists Work

There are a number of organizations that keep track of IP blacklists. IP addresses of possible spammers are collected either by individual users reporting spam, or by setting up “honeypots.” A honeypot is a monitored mailbox or area of a network that is designed as a trap for detecting spammers. Another popular method for creating IP blacklists is to collect the links that are contained within spam emails (and only spam emails). URI blacklists include the domain names and IP addresses of spam links included in spam emails.

Spam protection software is usually built into most mail servers, which reference any incoming emails against these public DNS blacklists. When a mail transfer agent queries a DNS seeking the hostname for the recipient’s mail server, it will usually check the sender’s domain and IP address against one or more IP blacklists. Depending on the mail server’s settings, the message will be rejected or discarded if the sender’s IP address matches one found on the IP blacklist.

Getting Removed from Blacklists

If your email account is hijacked by a spammer or hacker, or if you unknowingly share a shared web server with a spammer, your IP address may also be flagged as spam. You may also be added to a spam list or spam database if you are reported for abuse for a mistaken or disgruntled email user. For example, Cragislist.org posters are often flagged as spammers by competitors or if a Craigslist user misinterpreted the terms of the posting.

You can often get removed from a blacklist by appealing to the operator of the blacklist. When you use the IP blacklist lookup tool, you’ll be able to see which blacklists your IP address is included in. Take note of these blacklists and get in contact with the organization or individual who is responsible for maintaining the list.