###################### IPTABLES ########################
*NATING = network address translation.
*PATING = port address translation.
*What is Routing
ANS :- forwarding the packet from 1 interface to another interface.
Postrouting - After routing change the source ip address.
To hide the internel network (Dnat).
Prerouting - Before routing change the destination ip address.(Snat)
INPUT Chain - To configure in filter tables.
Targets --> ACCEPT,DROP,REJECT.
drop - no acknoledgement
reject - get acknoledgement.
icmp - internet control messege protocol.
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1)To Configure the iptables command is.
#iptabls
Filter NAT Mangle
INPUT PREROUTING INPUT
CHAINS:- OUTPUT POSTROUTING OUTPUT
FORWARD OUTPUT PREROUTING
POSTROUTING
FORWARD
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1)To apply the rules.
ACCEPT,DROP,REJECT.
-L --> To listening
-A --> To append
-p --> Protocol
-j --> To jump
-F --> To flush
2)To check whether the rule is applied or not.
#iptables -L
3)To remove the previous rules.
#iptables -F
4)To remove the rule.
#iptables -D
5)To insert a rule.
#iptables -I
6)To install the rules.
1)(ping)input traficc block.
#iptables -A INPUT -p icmp -j DROP/reject
2)To block perticuler matchine.
#iptables -A INPUT -p icmp -s 10.0.0.1 -j DROP/reject
3)To allow 1 matchine & block other all traffic.
#iptables -A INPUT -p icmp -s ! 10.0.0.1 -j DROP/reject
4)To block http service.
#iptables -A INPUT -p tcp --dport 80 -j DROP/reject
7)To set the iptables rules Permanent.
first set the rules.
#service iptables save
8)To delet the set rules.
#rm /etc/sysconfig/iptables
9)To remove a rule from the chain.
#iptables -D INPUT 1 -t filter
################### END #########################
