Public Block Lists of Malicious IPs and URLs

The following is a list of websites that maintain and provide public lists of known and suspected malicious sources. These lists can be used for preventing malware infections, for managing incoming email, or for testing purposes. 

Malware Block Lists (Domains/URLs)

IP Address Block Lists

Phishing Block Lists (Domains/URLs)

Spam Domain Block Lists

Notable Links

Has your IP address been blacklisted? You can use the following tools to find out.

more info http://www.selectrealsecurity.com/public-block-lists