Does my server use blacklists?

Yes, your server uses two primary blacklists to help reduce spam receipt:

zen.spamhaus.org is a large, but relatively low aggressiveness list. http://www.spamhaus.org/
zen.spamhaus.org is Spamhaus's compilation list, containing entries from each of their other lists. It's a large list but it is generally considered very clean.

bl.spamcop.net is a large, and aggressive list maintained by subscribers. http://www.spamcop.net/
SpamCop is an organization of users, admins, and servers who work to eliminate spam. They maintain a blacklist of IP addresses from people they consider to be spammers. Most of the spammers are reported by SpamCop users, so they may or may not be actually sending out spam.

 

We may add or remove blacklists from time to time, depending on the needs of those who share your server, and usefulness of the lists.

Other low aggressiveness may include:
combined.njabl.org
list.dsbl.org
cbl.abuseat.org
dnsbl.net.au
relays.ordb.org
multihop.dsbl.org