<s>
Linux	B-Operating_System
IP	O
Firewalling	O
Chains	O
,	O
normally	O
called	O
ipchains	B-Application
,	O
is	O
free	B-Application
software	I-Application
to	O
control	O
the	O
packet	B-Protocol
filter	I-Protocol
or	O
firewall	B-Application
capabilities	O
in	O
the	O
2.2	O
series	O
of	O
Linux	B-Operating_System
kernels	I-Operating_System
.	O
</s>
<s>
It	O
superseded	O
ipfirewall	B-Protocol
(	O
managed	O
by	O
ipfwadm	O
command	O
)	O
,	O
but	O
was	O
replaced	O
by	O
iptables	B-Application
in	O
the	O
2.4	O
series	O
.	O
</s>
<s>
Unlike	O
iptables	B-Application
,	O
ipchains	B-Application
is	O
stateless	O
.	O
</s>
<s>
It	O
is	O
a	O
rewrite	O
of	O
Linux	B-Operating_System
's	O
previous	O
IPv4	B-Protocol
firewall	B-Application
,	O
ipfirewall	B-Protocol
.	O
</s>
<s>
This	O
newer	O
ipchains	B-Application
was	O
required	O
to	O
manage	O
the	O
packet	B-Protocol
filter	I-Protocol
in	O
Linux	B-Operating_System
kernels	I-Operating_System
starting	O
with	O
version	O
2.1.102	O
(	O
which	O
was	O
a	O
2.2	O
development	O
release	O
)	O
.	O
</s>
<s>
Patches	O
are	O
also	O
available	O
to	O
add	O
ipchains	B-Application
to	O
2.0	O
and	O
earlier	O
2.1	O
series	O
kernels	B-Operating_System
.	O
</s>
<s>
Improvements	O
include	O
larger	O
maxima	O
for	O
packet	O
counting	O
,	O
filtering	O
for	O
fragmented	B-Protocol
packets	I-Protocol
and	O
a	O
wider	O
range	O
of	O
protocols	O
,	O
and	O
the	O
ability	O
to	O
match	O
packets	O
based	O
on	O
the	O
inverse	O
of	O
a	O
rule	O
.	O
</s>
<s>
The	O
ipchains	B-Application
suite	O
also	O
included	O
some	O
shell	O
scripts	O
for	O
easier	O
maintenance	O
and	O
to	O
emulate	O
the	O
behavior	O
of	O
the	O
old	O
ipfwadm	O
command	O
.	O
</s>
<s>
The	O
ipchains	B-Application
software	O
was	O
superseded	O
by	O
the	O
iptables	B-Application
system	O
in	O
Linux	B-Operating_System
kernel	I-Operating_System
2.4	I-Operating_System
and	O
above	O
,	O
which	O
was	O
in	O
turn	O
superseded	O
by	O
the	O
nftables	B-Application
system	O
in	O
2014	O
.	O
</s>
