<s>
The	O
Network	O
News	O
Transfer	O
Protocol	O
(	O
NNTP	O
)	O
is	O
an	O
application	O
protocol	O
used	O
for	O
transporting	O
Usenet	B-Application
news	I-Application
articles	O
(	O
netnews	B-Application
)	O
between	O
news	B-Application
servers	I-Application
,	O
and	O
for	O
reading/posting	O
articles	O
by	O
the	O
end	O
user	O
client	O
applications	O
.	O
</s>
<s>
Usenet	B-Application
was	O
originally	O
designed	O
based	O
on	O
the	O
UUCP	B-Protocol
network	O
,	O
with	O
most	O
article	O
transfers	O
taking	O
place	O
over	O
direct	O
point-to-point	B-Architecture
telephone	O
links	O
between	O
news	B-Application
servers	I-Application
,	O
which	O
were	O
powerful	O
time-sharing	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
As	O
local	B-General_Concept
area	I-General_Concept
networks	I-General_Concept
and	O
Internet	O
participation	O
proliferated	O
,	O
it	O
became	O
desirable	O
to	O
allow	O
newsreaders	B-Protocol
to	O
be	O
run	O
on	O
personal	O
computers	O
connected	O
to	O
local	B-General_Concept
networks	I-General_Concept
.	O
</s>
<s>
The	O
resulting	O
protocol	O
was	O
NNTP	O
,	O
which	O
resembled	O
the	O
Simple	B-Protocol
Mail	I-Protocol
Transfer	I-Protocol
Protocol	I-Protocol
(	O
SMTP	B-Protocol
)	O
but	O
was	O
tailored	O
for	O
exchanging	O
newsgroup	B-Application
articles	O
.	O
</s>
<s>
A	O
newsreader	B-Protocol
,	O
also	O
known	O
as	O
a	O
news	B-Protocol
client	I-Protocol
,	O
is	O
a	O
software	O
application	O
that	O
reads	O
articles	O
on	O
Usenet	B-Application
,	O
either	O
directly	O
from	O
the	O
news	B-Application
server	I-Application
's	O
disks	O
or	O
via	O
the	O
NNTP	O
.	O
</s>
<s>
The	O
well-known	B-Protocol
TCP	I-Protocol
port	I-Protocol
119	O
is	O
reserved	O
for	O
NNTP	O
.	O
</s>
<s>
Well-known	B-Protocol
TCP	I-Protocol
port	I-Protocol
433	O
(	O
NNSP	O
)	O
may	O
be	O
used	O
when	O
doing	O
a	O
bulk	O
transfer	O
of	O
articles	O
from	O
one	O
server	O
to	O
another	O
.	O
</s>
<s>
When	O
clients	O
connect	O
to	O
a	O
news	B-Application
server	I-Application
with	O
Transport	B-Protocol
Layer	I-Protocol
Security	I-Protocol
(	O
TLS	O
)	O
,	O
TCP	O
port	O
563	O
is	O
often	O
used	O
.	O
</s>
<s>
This	O
is	O
sometimes	O
referred	O
to	O
as	O
NNTPS	B-Protocol
.	O
</s>
<s>
Alternatively	O
,	O
a	O
plain-text	O
connection	O
over	O
port	O
119	O
may	O
be	O
changed	O
to	O
use	O
TLS	O
via	O
the	O
STARTTLS	B-Protocol
command	O
.	O
</s>
<s>
At	O
the	O
same	O
time	O
,	O
the	O
IETF	O
also	O
released	O
,	O
which	O
specifies	O
the	O
use	O
of	O
Transport	B-Protocol
Layer	I-Protocol
Security	I-Protocol
(	O
TLS	O
)	O
via	O
NNTP	O
over	O
STARTTLS	B-Protocol
.	O
</s>
<s>
This	O
protocol	O
was	O
never	O
completed	O
or	O
fully	O
implemented	O
,	O
but	O
the	O
name	O
persisted	O
in	O
InterNetNews	B-Application
's	O
(	O
INN	O
)	O
nnrpd	O
program	O
.	O
</s>
