<s>
The	O
Digital	B-Operating_System
Audio	I-Operating_System
Access	I-Operating_System
Protocol	I-Operating_System
(	O
DAAP	O
)	O
is	O
the	O
proprietary	O
protocol	O
introduced	O
by	O
Apple	O
in	O
its	O
iTunes	B-Operating_System
software	O
to	O
share	O
media	O
across	O
a	O
local	O
network	O
.	O
</s>
<s>
The	O
DAAP	O
protocol	O
was	O
originally	O
introduced	O
in	O
iTunes	B-Operating_System
version	O
4.0	O
.	O
</s>
<s>
Initially	O
,	O
Apple	O
did	O
not	O
officially	O
release	O
a	O
protocol	O
description	O
,	O
but	O
it	O
has	O
been	O
reverse-engineered	O
to	O
a	O
sufficient	O
degree	O
that	O
reimplementations	O
of	O
the	O
protocol	O
for	O
non-iTunes	O
platforms	O
have	O
been	O
possible	O
.	O
</s>
<s>
A	O
DAAP	O
server	O
is	O
a	O
specialized	O
HTTP	B-Protocol
server	O
,	O
which	O
performs	O
two	O
functions	O
.	O
</s>
<s>
Requests	O
are	O
sent	O
to	O
the	O
server	O
by	O
the	O
client	O
in	O
form	O
of	O
URLs	O
and	O
are	O
responded	O
to	O
with	O
data	O
in	O
mime-type	O
,	O
which	O
can	O
be	O
converted	O
to	O
XML	B-Protocol
by	O
the	O
client	O
.	O
</s>
<s>
iTunes	B-Operating_System
uses	O
the	O
zeroconf	B-Application
(	O
also	O
known	O
as	O
Bonjour	B-Application
)	O
service	O
to	O
announce	O
and	O
discover	O
DAAP	O
shares	O
on	O
a	O
local	O
subnet	B-Protocol
.	O
</s>
<s>
The	O
DAAP	O
service	O
uses	O
TCP	B-Protocol
port	O
3689	O
by	O
default	O
.	O
</s>
<s>
The	O
other	O
,	O
Digital	O
Photo	O
Access	O
Protocol	O
(	O
DPAP	O
)	O
,	O
is	O
used	O
by	O
iPhoto	B-Operating_System
for	O
sharing	O
images	O
.	O
</s>
<s>
They	O
both	O
rely	O
on	O
an	O
underlying	O
protocol	O
,	O
Digital	B-Operating_System
Media	I-Operating_System
Access	I-Operating_System
Protocol	I-Operating_System
(	O
DMAP	O
)	O
.	O
</s>
<s>
Early	O
versions	O
of	O
iTunes	B-Operating_System
allowed	O
users	O
to	O
connect	O
to	O
shares	O
across	O
the	O
Internet	O
,	O
however	O
,	O
in	O
recent	O
versions	O
only	O
computers	O
on	O
the	O
same	O
subnet	B-Protocol
can	O
share	O
music	O
(	O
workarounds	O
such	O
as	O
port	B-Protocol
tunneling	I-Protocol
are	O
possible	O
)	O
.	O
</s>
<s>
More	O
recent	O
versions	O
of	O
iTunes	B-Operating_System
also	O
limit	O
the	O
number	O
of	O
clients	O
to	O
5	O
unique	O
IP	B-Protocol
addresses	I-Protocol
within	O
a	O
24-hour	O
period	O
.	O
</s>
<s>
DAAP	O
has	O
also	O
been	O
implemented	O
in	O
other	O
non-iTunes	O
media	O
applications	O
such	O
as	O
Banshee	B-Language
,	O
Amarok	B-Language
,	O
Exaile	B-Language
(	O
with	O
a	O
plugin	O
)	O
,	O
Songbird	B-Application
(	O
with	O
a	O
plugin	O
)	O
,	O
Rhythmbox	B-Language
,	O
and	O
WiFiTunes	O
.	O
</s>
<s>
Beginning	O
with	O
iTunes	B-Operating_System
4.2	O
,	O
Apple	O
introduced	O
authentication	O
to	O
DAAP	O
sharing	O
,	O
meaning	O
that	O
the	O
only	O
clients	O
that	O
could	O
connect	O
to	O
iTunes	B-Operating_System
servers	I-Operating_System
were	O
other	O
instances	O
of	O
iTunes	B-Operating_System
.	O
</s>
<s>
This	O
was	O
further	O
modified	O
in	O
iTunes	B-Operating_System
4.5	O
to	O
use	O
a	O
custom	O
hashing	O
algorithm	O
,	O
rather	O
than	O
the	O
standard	O
MD5	B-Algorithm
function	O
used	O
previously	O
.	O
</s>
<s>
This	O
does	O
not	O
affect	O
third-party	O
DAAP	O
servers	O
,	O
but	O
all	O
current	O
DAAP	O
clients	O
(	O
including	O
official	O
iTunes	B-Operating_System
before	O
iTunes	B-Operating_System
7.0	O
)	O
will	O
fail	O
to	O
connect	O
to	O
an	O
iTunes	B-Operating_System
7.0	O
server	O
,	O
receiving	O
a	O
'	O
403	O
Forbidden	O
 '	O
HTTP	B-Protocol
error	O
.	O
</s>
