<s>
Unbound	B-Protocol
is	O
a	O
validating	O
,	O
recursive	O
,	O
and	O
caching	O
DNS	O
resolver	O
product	O
from	O
NLnet	B-General_Concept
Labs	I-General_Concept
.	O
</s>
<s>
It	O
is	O
distributed	O
free	O
of	O
charge	O
in	O
open-source	B-Application
form	O
under	O
the	O
BSD	B-Operating_System
license	I-Operating_System
.	O
</s>
<s>
Originally	O
designed	O
by	O
Jakob	O
Schlyter	O
of	O
Kirei	O
and	O
Roy	O
Arends	O
of	O
Nominet	O
in	O
2004	O
,	O
funding	O
was	O
provided	O
by	O
VeriSign	O
and	O
ep.net	O
to	O
develop	O
a	O
prototype	O
written	O
in	O
Java	B-Language
(	O
David	O
Blacka	O
and	O
Matt	O
Larson	O
,	O
VeriSign	O
)	O
.	O
</s>
<s>
In	O
2006	O
,	O
the	O
prototype	O
was	O
re-written	O
for	O
high-performance	O
in	O
the	O
C	B-Language
programming	I-Language
language	I-Language
by	O
NLnet	B-General_Concept
Labs	I-General_Concept
.	O
</s>
<s>
Unbound	B-Protocol
is	O
designed	O
as	O
a	O
set	O
of	O
modular	O
components	O
that	O
incorporate	O
modern	O
features	O
,	O
such	O
as	O
enhanced	O
security	O
(	O
DNSSEC	B-Protocol
)	O
validation	O
,	O
Internet	B-Protocol
Protocol	I-Protocol
Version	I-Protocol
6	I-Protocol
(	O
IPv6	B-Protocol
)	O
,	O
and	O
a	O
client	O
resolver	O
application	B-Application
programming	I-Application
interface	I-Application
library	O
as	O
an	O
integral	O
part	O
of	O
the	O
architecture	O
.	O
</s>
<s>
Originally	O
written	O
for	O
POSIX-compatible	O
Unix-like	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
,	O
it	O
runs	O
on	O
FreeBSD	B-Operating_System
,	O
OpenBSD	B-Operating_System
,	O
NetBSD	B-Device
,	O
macOS	B-Application
,	O
and	O
Linux	B-Application
,	O
as	O
well	O
as	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
Unbound	B-Protocol
has	O
supplanted	O
the	O
Berkeley	O
Internet	O
Name	O
Daemon	O
(	O
BIND	B-Protocol
)	O
as	O
the	O
default	O
,	O
base-system	O
name	B-Protocol
server	I-Protocol
in	O
FreeBSD	B-Operating_System
and	O
OpenBSD	B-Operating_System
,	O
where	O
it	O
is	O
perceived	O
as	O
smaller	O
,	O
more	O
modern	O
,	O
and	O
more	O
secure	O
for	O
most	O
applications	O
.	O
</s>
