The Spamhaus ZEN Operation queries IP addresses and domains against the ZEN blocklist.

zen.spamhaus.org

ZEN is the combination of all Spamhaus IP-based DNSBLs into one single powerful and comprehensive blocklist to make querying faster and simpler. It contains the SBL, SBLCSS, XBL and PBL blocklists.

zen.spamhaus.org should be the only spamhaus.org DNSBL in your IP blocklist configuration. You should not use ZEN together with other Spamhaus IP blocklists, or with blocklists already included in our zones (such as the CBL) or you will simply be wasting DNS queries and slowing your mail queue.

zen.spamhaus.org replaces sbl-xbl.spamhaus.org in most configurations. If you are currently using sbl-xbl.spamhaus.org you should replace sbl-xbl.spamhaus.org with zen.spamhaus.org.