IP Tables Simplified

IP Tables Simplified

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what are iptables ??

* Its firewall control Application , actual firewal is Netfilter , is controled by iptables-application.

what are funtions of iptables ??

* It Controls Network/Transport Layer (3 & 4) functions.

* Mechanism for Packet Filtering.

Nat-ing , Mangle-ing

*RAM Contains User Space and Kernel Space.

Netfilter is in kernel , users cant interact with directly.

iptables is user space so that user can interact.

**Netfilter contains tables , tables contains chains , and chains contain rules.

*Netfilter/kernel Firewal -> Tables ->Chains -> Rules.

*Tables > are  Filter table , Nat table  . Mangle table

*Chains > are Input , Output , Forward , Pre-Routing , PostRouting

* Decisions are ACCEPT , Reject , Drop , DNAT , SNAT, Redirect Masquerade.

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syntax:

iptables

      -t TableName

       Rule position/action ChaineName

       Condition1 AND Condition2 AND Condition 3

       -j JumpDestination/Action to take

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RULE

iptables

  -t table

   -A INPUT

    -i eth0 -p tcp --destination-port 80

    -j Reject / Drop /accept

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