spamd spam deferral daemon rejects fake emails. It is designed for
efficiency, so that the receiving host is not slowed down.
spamd divides sending hosts into three types:
Blacklisted hosts are diverted to
spamd and tarpitted. In other words, they are
communicated with very slowly to consume the sender’s resources.
Mail is rejected with either a 450 or 550 error message. A blacklisted
host will not be allowed to talk to a real mail server.
Whitelisted hosts do not talk to
spamd. Their connections are instead
sent to a real mail server, such as
Greylisted hosts are diverted to
spamd if it is not yet known whether they
are likely spammers. They are sent a temporary failure message when they try to
spamdcommand first appeared in OpenBSD 3.3.
- spamd(8) - OpenBSD manual pages
- spamd.conf(5) - OpenBSD manual pages