How to Monitor IP Blacklists

If you operate outbound email services, it’s important to know when one of the IP addresses from which you send email has been listed on a blacklist. When an IP is blacklisted, delivery from the IP can be severely affected, causing a surge in customer support issues.

How to Monitor IP Blacklists

If you have only a small number of IP addresses, the are various IP blacklist monitoring services available on the web, which can monitor your IP addresses for you and send alerts when an IP becomes listed. If you have a large number of IP addresses, it becomes more cost effective to develop an in-house monitoring solution, which can query each blacklist against each of your IP addresses.

List of the Most Important IP Blacklists

Not all IP blacklists are created equal: Some IP blacklists are far more important than others, because a larger
number of email receivers implement these blacklists as tools in their anti-spam arsenal. The following is a list of the most important IP blacklists, which you should be monitoring.

  • Spamhaus – Several distinct IP reputation lists should be monitored continuously, including:
    • Spamhaus Block List (SBL) – generated from continuous anti-spam research, with human intervention
    • Exploits Block List (XBL) – mostly automated, but equally as important as the SBL
  • Spam and Open Relay Blocking System – very influential
  • UCEPROTECT – fully automated, and asks for payment for removal requests


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Monitoring IP blacklists is challenging and time-consuming

MailChannels Outbound Filtering delivers email from IP addresses that you don't have to monitor