We make use of public blacklists of known spammers and other troublesome email addresses to limit the amount of spam coming into the University's mail systems.
Spamhaus Zen comprises of three block lists run by the Spamhaus Project.
The three block lists are:
- Spamhaus Block List (SBL) which is a widely-used and high-profile list of IP addresses belonging to spammers.
- Composite Block List (CBL) which is a list of well-known compromised addresses known to relay spam.
- Policy Block List (PBL) is a list of IP addresses which are expected by their owning Internet Service Providers (ISPs) to emit mail only via the ISP's mail servers and not directly to other mail systems.