What is a DNSBL?

Domain name system blacklist or a DNS blacklist is a software mechanism that helps or facilitates mail server providers to block IP address that send spam content.

There are various DNS blacklists service providers in the market today. And the mechanisms of how they identify and block spam IPs vary from one another. In general, most mail service providers offer a DNS service by default.

Common reasons:

1. Spamming content
2. Phishing attacks
3. Marketing mails - inappropriate mail list or too many unsubscibes
4. Email spoofing
5. Inappropriate website content such as blackmarkets or pornographic content

How to blacklist check an IP address or a domain?

A blacklisted IP address or Domain could cost your reputation and business. To check whether your IP address or Domain is blacklisted, use Site24x7's blacklist checker - simply key in your IP address or domain name and Site24x7's blacklist checker tool will verify the given address across the popular 10+ blacklist databases and let you know if your domain or site is blacklisted or not.

How to fix a blacklisted IP/Domain/Email?

Check and figure out the services / blacklist provides that have blacklisted your site. Create a request to delist your site. The procedure may vary from one service to another and hence follow the steps accordingly.