Spamhaus ZEN
ZEN is a combination of all of the Spamhaus IP-based DNSBLs in a single powerful and comprehensive blocklist to make querying faster and simpler. It includes SBL, SBLCSS, XBL, and PBL blocklists to find blacklisted IPs in seconds.
Blacklist
The IP addresses of email servers worldwide can be scanned in seconds to identify blacklisted email servers and quickly take any needed action. Since it doesn’t require any additional API key, it takes seconds to enable the Spamhaus Zen integration on the platform.