<s>
In	O
computing	O
,	O
the	O
Hesiod	B-Protocol
name	O
service	O
originated	O
in	O
Project	B-Operating_System
Athena	I-Operating_System
(	O
1983	O
–	O
1991	O
)	O
.	O
</s>
<s>
It	O
uses	O
DNS	B-Protocol
functionality	O
to	O
provide	O
access	O
to	O
databases	O
of	O
information	O
that	O
change	O
infrequently	O
.	O
</s>
<s>
In	O
Unix	B-Application
environments	O
it	O
often	O
serves	O
to	O
distribute	O
information	O
kept	O
in	O
the	O
,	O
,	O
and	O
files	O
,	O
among	O
others	O
.	O
</s>
<s>
Frequently	O
an	O
LDAP	B-Protocol
server	O
is	O
used	O
to	O
distribute	O
the	O
same	O
kind	O
of	O
information	O
that	O
Hesiod	B-Protocol
does	O
.	O
</s>
<s>
However	O
,	O
because	O
Hesiod	B-Protocol
can	O
leverage	O
existing	O
DNS	B-Protocol
servers	O
,	O
deploying	O
it	O
to	O
a	O
network	O
is	O
fairly	O
easy	O
.	O
</s>
<s>
In	O
a	O
Unix-like	B-Operating_System
system	I-Operating_System
users	O
usually	O
have	O
a	O
line	O
in	O
the	O
file	O
for	O
each	O
local	O
user	O
like	O
:	O
</s>
<s>
user	O
's	O
primary	O
group	B-Application
id	I-Application
(	O
unsigned	O
integer	O
)	O
;	O
</s>
<s>
Gecos	B-Operating_System
field	I-Operating_System
(	O
four	O
comma	O
separated	O
fields	O
,	O
string	O
)	O
;	O
</s>
<s>
This	O
is	O
where	O
Hesiod	B-Protocol
enters	O
.	O
</s>
<s>
Instead	O
of	O
having	O
this	O
information	O
stored	O
on	O
every	O
machine	O
,	O
Hesiod	B-Protocol
stores	O
it	O
in	O
records	O
on	O
your	O
DNS	B-Protocol
server	O
.	O
</s>
<s>
Then	O
each	O
client	O
can	O
query	O
the	O
DNS	B-Protocol
server	O
for	O
this	O
information	O
instead	O
of	O
looking	O
for	O
it	O
locally	O
.	O
</s>
<s>
In	O
BIND	B-Protocol
the	O
records	O
for	O
the	O
above	O
user	O
might	O
look	O
something	O
like	O
:	O
</s>
<s>
The	O
Domain	B-Protocol
Name	I-Protocol
System	I-Protocol
has	O
a	O
special	O
class	O
of	O
service	O
for	O
Hesiod	B-Protocol
's	O
purpose	O
.	O
</s>
<s>
The	O
/etc/hesiod.conf	O
file	O
for	O
this	O
setup	O
might	O
look	O
something	O
like	O
:	O
</s>
<s>
The	O
/etc/resolv.conf	O
file	O
uses	O
the	O
name	O
servers	O
that	O
have	O
the	O
Hesiod	B-Protocol
records	O
.	O
</s>
<s>
What	O
happens	O
here	O
is	O
that	O
the	O
foo	O
and	O
the	O
passwd	B-Protocol
are	O
combined	O
with	O
the	O
lhs	O
and	O
rhs	O
values	O
in	O
the	O
/etc/hesiod.conf	O
file	O
to	O
create	O
a	O
fully	O
qualified	O
name	O
of	O
foo.passwd.ns.example.net	O
.	O
</s>
<s>
The	O
DNS	B-Protocol
server	O
is	O
then	O
queried	O
for	O
this	O
entry	O
and	O
returns	O
the	O
value	O
of	O
that	O
record	O
.	O
</s>
