<s>
spamd	B-Application
is	O
an	O
ISC-licensed	B-License
lightweight	O
spam-deferral	O
daemon	B-Operating_System
written	O
under	O
the	O
umbrella	O
of	O
the	O
OpenBSD	B-Operating_System
project	I-Operating_System
.	O
</s>
<s>
spamd	B-Application
works	O
directly	O
with	O
smtp	O
connections	O
,	O
and	O
supports	O
features	O
such	O
as	O
greylisting	O
,	O
minimising	O
false	O
positives	O
compared	O
to	O
a	O
system	O
that	O
does	O
full-body	O
analysis	O
.	O
</s>
<s>
spamd	B-Application
is	O
designed	O
to	O
work	O
in	O
conjunction	O
with	O
pf(4 )	O
,	O
and	O
should	O
be	O
fully	O
functional	O
on	O
any	O
POSIX	O
system	O
where	O
pf	B-Protocol
is	O
available	O
,	O
i.e.	O
</s>
<s>
OpenBSD	B-Operating_System
,	O
NetBSD	B-Device
,	O
FreeBSD	B-Operating_System
and	O
DragonFly	B-Application
BSD	I-Application
.	O
</s>
<s>
Spamd	B-Application
is	O
most	O
useful	O
in	O
preventing	O
inbound	O
spam	O
from	O
reaching	O
mail	B-Protocol
servers	I-Protocol
.	O
</s>
<s>
It	O
can	O
also	O
be	O
used	O
as	O
a	O
partial	O
application	B-Application
level	O
proxy	B-Application
to	O
ensure	O
that	O
external	O
mail	B-Protocol
servers	I-Protocol
connecting	O
to	O
internal	O
mail	B-Protocol
servers	I-Protocol
behave	O
legitimately	O
.	O
</s>
<s>
Additionally	O
,	O
spamd	B-Application
can	O
be	O
very	O
useful	O
in	O
preventing	O
outgoing	O
spam	O
from	O
systems	O
that	O
may	O
be	O
compromised	O
or	O
under	O
the	O
control	O
of	O
spammers	O
.	O
</s>
