<s>
In	O
Internet	O
computing	O
,	O
NSD	B-Protocol
(	O
for	O
"	O
name	B-Protocol
server	I-Protocol
daemon	I-Protocol
"	O
)	O
is	O
an	O
open-source	B-Application
Domain	B-Protocol
Name	I-Protocol
System	I-Protocol
(	O
DNS	B-Protocol
)	O
server	B-Application
.	O
</s>
<s>
It	O
was	O
developed	O
by	O
NLnet	B-General_Concept
Labs	I-General_Concept
of	O
Amsterdam	O
in	O
cooperation	O
with	O
the	O
RIPE	O
NCC	O
,	O
from	O
scratch	O
as	O
an	O
authoritative	O
name	B-Protocol
server	I-Protocol
(	O
i.e.	O
,	O
not	O
implementing	O
the	O
recursive	O
caching	O
function	O
by	O
design	O
)	O
.	O
</s>
<s>
used	O
by	O
higher	O
level	O
name	B-Protocol
servers	I-Protocol
and	O
thus	O
increase	O
the	O
resilience	O
of	O
DNS	B-Protocol
against	O
software	O
flaws	O
or	O
exploits	O
.	O
</s>
<s>
NSD	B-Protocol
uses	O
BIND-style	O
zone-files	O
(	O
zone-files	O
used	O
under	O
BIND	B-Protocol
can	O
usually	O
be	O
used	O
unmodified	O
in	O
NSD	B-Protocol
,	O
once	O
entered	O
into	O
the	O
NSD	B-Protocol
configuration	O
)	O
.	O
</s>
<s>
NSD	B-Protocol
uses	O
zone	O
information	O
compiled	O
via	O
zonec	O
into	O
a	O
binary	O
database	O
file	O
(	O
nsd.db	O
)	O
which	O
allows	O
fast	O
startup	O
of	O
the	O
NSD	B-Protocol
name-service	O
daemon	O
,	O
and	O
allows	O
syntax-structural	O
errors	O
in	O
Zone-Files	O
to	O
be	O
flagged	O
at	O
compile-time	O
(	O
before	O
being	O
made	O
available	O
to	O
NSD	B-Protocol
service	O
itself	O
)	O
.	O
</s>
<s>
The	O
collection	O
of	O
programs/processes	O
that	O
make-up	O
NSD	B-Protocol
are	O
designed	O
so	O
that	O
the	O
NSD	B-Protocol
daemon	O
itself	O
runs	O
as	O
a	O
non-privileged	O
user	O
and	O
can	O
be	O
easily	O
configured	O
to	O
run	O
in	O
a	O
Chroot	B-Application
jail	I-Application
,	O
such	O
that	O
security	O
flaws	O
in	O
the	O
NSD	B-Protocol
daemon	O
are	O
not	O
so	O
likely	O
to	O
result	O
in	O
system-wide	O
compromise	O
as	O
without	O
such	O
measures	O
.	O
</s>
<s>
As	O
of	O
May	O
,	O
2018	O
,	O
four	O
of	O
the	O
Internet	O
root	B-Application
nameservers	I-Application
are	O
using	O
NSD	B-Protocol
:	O
</s>
<s>
k.root-servers.net	O
was	O
switched	O
to	O
NSD	B-Protocol
on	O
February	O
19	O
,	O
2003	O
.	O
</s>
<s>
One	O
of	O
the	O
2	O
load-balanced	O
servers	O
for	O
h.root-servers.net	O
(	O
called	O
"	O
H1	O
"	O
,	O
"	O
H2	O
"	O
)	O
was	O
switched	O
to	O
NSD	B-Protocol
,	O
and	O
now	O
there	O
are	O
3	O
servers	O
all	O
running	O
NSD	B-Protocol
(	O
called	O
"	O
H1	O
"	O
,	O
"	O
H2	O
"	O
,	O
"	O
H3	O
"	O
)	O
.	O
</s>
<s>
l.root-servers.net	O
switched	O
to	O
NSD	B-Protocol
on	O
February	O
6	O
,	O
2007	O
.	O
</s>
<s>
d.root-servers.net	O
was	O
switched	O
to	O
NSD	B-Protocol
in	O
May	O
2018	O
.	O
</s>
<s>
Several	O
other	O
TLDs	O
use	O
NSD	B-Protocol
for	O
part	O
of	O
their	O
servers	O
.	O
</s>
