<s>
The	O
djbdns	B-Protocol
software	O
package	O
is	O
a	O
DNS	B-Protocol
implementation	O
.	O
</s>
<s>
It	O
was	O
created	O
by	O
Daniel	O
J	O
.	O
Bernstein	O
in	O
response	O
to	O
his	O
frustrations	O
with	O
repeated	O
security	O
holes	O
in	O
the	O
widely	O
used	O
BIND	B-Protocol
DNS	B-Protocol
software	O
.	O
</s>
<s>
As	O
a	O
challenge	O
,	O
Bernstein	O
offered	O
a	O
$1000	O
prize	O
for	O
the	O
first	O
person	O
to	O
find	O
a	O
security	O
hole	O
in	O
djbdns	B-Protocol
,	O
which	O
was	O
awarded	O
in	O
March	O
2009	O
to	O
Matthew	O
Dempsky	O
.	O
</s>
<s>
,	O
djbdns	B-Protocol
's	O
tinydns	B-Protocol
component	O
was	O
the	O
second	O
most	O
popular	O
DNS	B-Protocol
server	O
in	O
terms	O
of	O
the	O
number	O
of	O
domains	O
for	O
which	O
it	O
was	O
the	O
authoritative	O
server	O
,	O
and	O
third	O
most	O
popular	O
in	O
terms	O
of	O
the	O
number	O
of	O
DNS	B-Protocol
hosts	O
running	O
it	O
.	O
</s>
<s>
djbdns	B-Protocol
has	O
never	O
been	O
vulnerable	O
to	O
the	O
widespread	O
cache	O
poisoning	O
vulnerability	O
reported	O
in	O
July	O
2008	O
,	O
but	O
it	O
has	O
been	O
discovered	O
that	O
it	O
is	O
vulnerable	O
to	O
a	O
related	O
attack	O
.	O
</s>
<s>
As	O
of	O
March	O
2009	O
,	O
there	O
are	O
a	O
number	O
of	O
forks	B-Application
,	O
one	O
of	O
which	O
is	O
dbndns	B-Application
(	O
part	O
of	O
the	O
Debian	O
Project	O
)	O
,	O
and	O
more	O
than	O
a	O
dozen	O
patches	O
to	O
modify	O
the	O
released	O
version	O
.	O
</s>
<s>
While	O
djbdns	B-Protocol
does	O
not	O
directly	O
support	O
DNSSEC	B-Protocol
,	O
there	O
are	O
third	O
party	O
patches	O
to	O
add	O
DNSSEC	B-Protocol
support	O
to	O
djbdns	B-Protocol
 '	O
authoritative-only	O
tinydns	B-Protocol
component	O
.	O
</s>
<s>
The	O
djbdns	B-Protocol
software	O
consists	O
of	O
servers	O
,	O
clients	O
,	O
and	O
miscellaneous	O
configuration	O
tools	O
.	O
</s>
<s>
dnscache	O
the	O
DNS	B-Protocol
resolver	O
and	O
cache	O
.	O
</s>
<s>
tinydns	B-Protocol
a	O
database-driven	O
DNS	B-Protocol
server	O
.	O
</s>
<s>
walldns	O
a	O
"	O
reverse	O
DNS	B-Protocol
wall	O
"	O
,	O
providing	O
IP	O
address-to-domain	O
name	O
lookup	O
only	O
.	O
</s>
<s>
rbldns	O
a	O
server	O
designed	O
for	O
DNS	B-Protocol
blacklisting	O
service	O
.	O
</s>
<s>
(	O
This	O
feature	O
is	O
now	O
a	O
standard	O
part	O
of	O
tinydns	B-Protocol
.	O
)	O
</s>
<s>
dnstrace	O
(	O
and	O
dnstracesort	O
)	O
comprehensive	O
testing	O
of	O
the	O
chains	O
of	O
authority	O
over	O
DNS	B-Protocol
servers	O
and	O
their	O
names	O
.	O
</s>
<s>
In	O
djbdns	B-Protocol
,	O
different	O
features	O
and	O
services	O
are	O
split	O
off	O
into	O
separate	O
programs	O
.	O
</s>
<s>
The	O
result	O
of	O
these	O
design	O
decisions	O
is	O
a	O
reduction	O
in	O
code	O
size	O
and	O
complexity	O
of	O
the	O
daemon	B-Operating_System
program	O
that	O
provides	O
the	O
core	O
function	O
of	O
answering	O
lookup	O
requests	O
.	O
</s>
<s>
Bernstein	O
asserts	O
that	O
this	O
is	O
true	O
to	O
the	O
spirit	O
of	O
the	O
Unix	B-Application
operating	I-Application
system	I-Application
,	O
and	O
makes	O
security	O
verification	O
much	O
simpler	O
.	O
</s>
<s>
On	O
December	O
28	O
,	O
2007	O
,	O
Bernstein	O
released	O
djbdns	B-Protocol
into	O
the	O
public	O
domain	O
.	O
</s>
<s>
Previously	O
the	O
package	O
was	O
distributed	O
free	O
of	O
charge	O
as	O
license-free	B-License
software	I-License
.	O
</s>
<s>
However	O
this	O
did	O
not	O
permit	O
the	O
distribution	O
of	O
modified	O
versions	O
of	O
djbdns	B-Protocol
,	O
which	O
was	O
one	O
of	O
the	O
core	O
principles	O
of	O
open-source	B-Application
software	I-Application
.	O
</s>
<s>
Consequently	O
,	O
it	O
was	O
not	O
included	O
in	O
those	O
Linux	B-Application
distributions	I-Application
which	O
required	O
all	O
components	O
to	O
be	O
open-source	B-Application
.	O
</s>
