<s>
R-tools	B-Protocol
are	O
a	O
set	O
of	O
Unix/Linux	O
tools	O
that	O
allow	O
basic	O
unsecured	O
administration	O
of	O
Unix/Linux	O
systems	O
by	O
establishing	O
a	O
Remote	B-Protocol
Shell	I-Protocol
.	O
</s>
<s>
Similar	O
in	O
nature	O
to	O
Telnet	B-Protocol
but	O
much	O
less	O
popular	O
,	O
R-tools	B-Protocol
is	O
considered	O
by	O
most	O
IT	O
professionals	O
to	O
be	O
dangerous	O
and	O
obsolete	O
.	O
</s>
<s>
The	O
much	O
preferred	O
way	O
to	O
do	O
a	O
remote	B-Protocol
shell	I-Protocol
is	O
ssh	B-Protocol
.	O
</s>
<s>
R-tools	B-Protocol
connects	O
over	O
TCP	O
port	O
513	O
with	O
the	O
command	O
rlogin	B-Application
,	O
r-tools	B-Protocol
is	O
considered	O
to	O
be	O
insecure	O
because	O
it	O
can	O
be	O
configured	O
to	O
only	O
require	O
a	O
hostname	O
and	O
username	O
;	O
transmissions	O
using	O
r-tools	B-Protocol
are	O
not	O
encrypted	O
.	O
</s>
<s>
rlogin	B-Application
is	O
the	O
command	O
used	O
to	O
establish	O
a	O
remote	B-Protocol
shell	I-Protocol
.	O
</s>
<s>
rsh	B-Protocol
will	O
login	O
,	O
execute	O
a	O
command	O
and	O
immediately	O
log	O
back	O
out	O
.	O
</s>
<s>
rcp	B-Application
will	O
login	O
,	O
copy	O
a	O
file	O
and	O
immediately	O
log	O
back	O
out	O
.	O
</s>
<s>
rwho	O
is	O
a	O
command	O
similar	O
to	O
finger	B-Application
that	O
will	O
output	O
a	O
list	O
of	O
logged-in	O
users	O
.	O
</s>
<s>
rexec	B-Application
is	O
similar	O
to	O
rsh	B-Protocol
but	O
runs	O
on	O
port	O
512	O
and	O
uses	O
different	O
syntax	O
.	O
</s>
