What is CSS?

Back

What is CSS?

The Spamhaus CSS is a component of the Spamhaus Blocklist (SBL).

The CSS list is an automatically produced dataset of IP addresses that are involved in sending low-reputation email. CSS mostly targets static spam emitters but may also include other senders that display a risk to our users, such as compromised hosts. CSS lists both IPv4 addresses (/32) and IPv6 addresses (/64 or larger). CSS listings are influenced by:

• Email showing indications of unsolicited nature;
• Having poor list-hygiene;
• Sending out bad email due to a compromise, insecure installation or misconfigured server;
• Other indicators of low reputation or abuse.

CSS listings are based on a wide range of inputs and are always the result of multiple events and heuristics.

Back