<s>
The	O
arptables	B-Protocol
computer	O
software	O
utility	O
is	O
a	O
network	O
administrator	O
's	O
tool	O
for	O
maintaining	O
the	O
Address	O
Resolution	O
Protocol	O
(	O
ARP	O
)	O
packet	O
filter	O
rules	O
in	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
firewall	B-Application
modules	O
.	O
</s>
<s>
The	O
tools	O
may	O
be	O
used	O
to	O
create	O
,	O
update	O
,	O
and	O
view	O
the	O
tables	O
that	O
contain	O
the	O
filtering	O
rules	O
,	O
similarly	O
to	O
the	O
iptables	B-Application
program	O
from	O
which	O
it	O
was	O
developed	O
.	O
</s>
<s>
Linux	B-Operating_System
kernel	I-Operating_System
2.4	I-Operating_System
only	O
offers	O
two	O
ARP	O
filtering	O
chains	O
,	O
INPUT	O
and	O
OUTPUT	O
,	O
and	O
Linux	B-Operating_System
kernel	I-Operating_System
2.6	I-Operating_System
adds	O
the	O
third	O
,	O
FORWARD	O
,	O
applied	O
when	O
bridging	O
packets	O
.	O
</s>
