<s>
Created	O
at	O
MIT	O
as	O
part	O
of	O
Project	B-Operating_System
Athena	I-Operating_System
,	O
Zephyr	B-Protocol
was	O
designed	O
as	O
an	O
instant	B-Application
messaging	I-Application
protocol	O
and	O
application-suite	O
with	O
a	O
heavy	O
Unix	B-Application
background	O
.	O
</s>
<s>
Using	O
the	O
"	B-Operating_System
do	I-Operating_System
one	I-Operating_System
thing	I-Operating_System
,	I-Operating_System
do	I-Operating_System
it	I-Operating_System
well	I-Operating_System
"	I-Operating_System
philosophy	I-Operating_System
of	O
Unix	B-Application
,	O
it	O
was	O
made	O
up	O
of	O
several	O
separate	O
programs	O
working	O
together	O
to	O
make	O
a	O
complete	O
messaging	O
system	O
.	O
</s>
<s>
Zephyr	B-Protocol
and	O
IRC	B-Protocol
were	O
the	O
first	O
widely	O
used	O
IP-based	O
instant-messaging	O
systems	O
.	O
</s>
<s>
Zephyr	B-Protocol
is	O
the	O
invention	O
of	O
Ciarán	O
Anthony	O
DellaFera	O
who	O
was	O
,	O
at	O
that	O
time	O
,	O
an	O
employee	O
of	O
Digital	O
Equipment	O
Corporation	O
and	O
a	O
Visiting	O
Research	O
Scientist	O
at	O
Project	B-Operating_System
Athena	I-Operating_System
.	O
</s>
<s>
The	O
design	O
originated	O
as	O
a	O
solution	O
to	O
the	O
"	O
reverse	O
Remote	B-Operating_System
Procedure	I-Operating_System
Call	I-Operating_System
(	O
RPC	O
)	O
"	O
problem	O
:	O
how	O
can	O
service	O
providers	O
(	O
servers	O
in	O
a	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
system	O
)	O
locate	O
and	O
communicate	O
with	O
service	O
users	O
.	O
</s>
<s>
The	O
initial	O
concept	O
emerged	O
from	O
conversations	O
between	O
Ciarán	O
and	O
Michael	O
R	O
.	O
Gretzinger	O
,	O
another	O
systems	O
engineer	O
at	O
Project	B-Operating_System
Athena	I-Operating_System
,	O
in	O
early	O
1986	O
.	O
</s>
<s>
By	O
mid	O
to	O
late	O
1986	O
Ciarán	O
had	O
distilled	O
the	O
problem	O
to	O
two	O
specific	O
issues	O
:	O
the	O
ability	O
to	O
locate	O
users	O
in	O
a	O
distributed	B-Architecture
computing	I-Architecture
environment	O
(	O
known	O
today	O
as	O
"	O
presence	O
detection	O
"	O
)	O
,	O
and	O
the	O
ability	O
to	O
deliver	O
scalable	O
,	O
light-weight	O
,	O
and	O
authentic	O
messages	O
in	O
a	O
distributed	B-Architecture
computing	I-Architecture
environment	O
.	O
</s>
<s>
The	O
Zephyr	B-Protocol
Development	O
Team	O
(	O
Mark	O
W	O
.	O
Eichin	O
,	O
Robert	O
S	O
.	O
French	O
,	O
David	O
C	O
.	O
Jedlinsky	O
,	O
John	O
T	O
.	O
Kohl	O
,	O
William	O
E	O
.	O
Sommerfeld	O
)	O
was	O
responsible	O
for	O
the	O
creation	O
of	O
the	O
initial	O
code-base	O
and	O
the	O
subsequent	O
releases	O
that	O
were	O
issued	O
throughout	O
the	O
late	O
1980s	O
.	O
</s>
<s>
Zephyr	B-Protocol
is	O
still	O
in	O
use	O
today	O
at	O
a	O
few	O
university	O
environments	O
such	O
as	O
Carnegie	O
Mellon	O
,	O
Iowa	O
State	O
,	O
University	O
of	O
Maryland	O
,	O
College	O
Park	O
,	O
Brown	O
University	O
and	O
MIT	O
.	O
</s>
<s>
It	O
has	O
been	O
largely	O
replaced	O
by	O
modern	O
and	O
more	O
popular	O
instant	B-Application
messenger	I-Application
systems	O
such	O
as	O
XMPP	B-Protocol
.	O
</s>
<s>
MIT	O
currently	O
operates	O
both	O
Zephyr	B-Protocol
and	O
XMPP	B-Protocol
.	O
</s>
<s>
Zephyr	B-Protocol
uses	O
UDP	B-Protocol
datagrams	O
sent	O
between	O
ports	O
2102	O
,	O
2103	O
,	O
and	O
2104	O
.	O
</s>
<s>
It	O
is	O
incompatible	O
with	O
most	O
routers	O
doing	O
NAT	B-Protocol
because	O
it	O
reports	O
the	O
internal	O
IP	B-Protocol
address	O
and	O
so	O
returning	O
datagrams	O
are	O
incorrectly	O
routed	O
.	O
</s>
<s>
Most	O
sites	O
have	O
deployed	O
Zephyr	B-Protocol
using	O
Kerberos	B-Protocol
4	I-Protocol
authentication	O
exclusively	O
,	O
though	O
in	O
late	O
2007	O
,	O
some	O
sites	O
,	O
including	O
Iowa	O
State	O
,	O
deployed	O
Zephyr	B-Protocol
using	O
Kerberos	B-Protocol
5	I-Protocol
.	O
</s>
<s>
has	O
always	O
had	O
Zephyr	B-Protocol
protocol	I-Protocol
support	O
.	O
</s>
<s>
Pidgin	B-Protocol
supports	O
the	O
Zephyr	B-Protocol
protocol	I-Protocol
since	O
version	O
0.11.0-pre10	O
(	O
April	O
13	O
,	O
2001	O
)	O
.	O
</s>
<s>
Adium	B-Protocol
added	O
support	O
for	O
Zephyr	B-Protocol
in	O
Version	O
0.70	O
(	O
October	O
18	O
,	O
2004	O
)	O
,	O
but	O
dropped	O
in	O
version	O
1.4b6	O
(	O
June	O
3	O
,	O
2009	O
)	O
.	O
</s>
