A dns spam blacklist lookup or blacklist is a database containing known internet addresses (or IPs) used by individuals or companies sending spam. Various ISP's and bandwidth providers subscribe to these DNS spam blacklist databases to filter out spam sent across their network or to their subscribers.

Some of the most widely checked DNSBL blacklists (DNS-based lists) are Spamcop, MAPS blacklist, SPAMHaus, CBL and Outblaze.

As a legitimate email marketer, you have to be concerned if your IP addresses are blacklisted on various dns blacklists and blocklists. If an IP address is blacklisted, email delivery rates decline as mail servers filter your email. To ensure opt-in emails are being delivered, it is crucial to monitor your IP addresses and use a CAN-SPAM compliant email marketing software like Mass Mailer or our other e-mailing services.

Please use these free DNS Spam Blacklist Lookup sites: