<s>
In	O
the	O
Domain	B-Protocol
Name	I-Protocol
System	I-Protocol
,	O
a	O
Uniform	B-Protocol
Resource	I-Protocol
Identifier	I-Protocol
(	O
URI	B-Protocol
)	O
record	O
(	O
RFC	O
7553	O
)	O
is	O
a	O
means	O
for	O
publishing	O
mappings	O
from	O
hostnames	O
to	O
URIs	B-Protocol
.	O
</s>
<s>
The	O
URI	B-Protocol
record	I-Protocol
is	O
expressed	O
in	O
a	O
master	O
file	O
in	O
the	O
following	O
format	O
:	O
</s>
<s>
proto	O
:	O
the	O
transport	O
protocol	O
of	O
the	O
desired	O
service	O
;	O
this	O
is	O
usually	O
either	O
TCP	B-Protocol
or	O
UDP	B-Protocol
.	O
</s>
<s>
TTL	O
:	O
standard	O
DNS	B-Protocol
time	B-Protocol
to	I-Protocol
live	I-Protocol
field	O
.	O
</s>
<s>
class	O
:	O
standard	O
DNS	B-Protocol
class	O
field	O
(	O
this	O
is	O
always	O
IN	O
)	O
.	O
</s>
