File for
configuration.
# vi /etc/sysctle.conf
To read the kernel for changes in
sysctle.conf.
# sysctle-p
(to get the list of rules been created)
#iptables –L
(its means firewall will accept all the
incoming connections)
#iptables –P input ACCEPT
(its means firewall
will DROP all the incoming connections)
# iptables –P input DROP
(its means firewall will drop only the
connection which comes for port no 21)
# iptables –A INPUT –p TCP –dport 21 –j DROP
IPTABLES common usage:
A =
Add rules
P =
protocols
d =
Destination
j =
jumps
(Flues all the rules)
# iptables –F
Add exception to firewall below rule will
accept the connection from only from 192.168.1.23 for port no 21.
# iptables –A INPUT –p tcp –-dport 21 –s!192.168.1.23 –j DROP |
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