CODEWITHSUNDEEP
network-programmingfirewalliptablesnetwork-security
Layla
Layla

Reputation: 143

Write IPTable rules

How to write IPTable rules such that the administrator on 128.238.66.2 has ssh access to the firewall and no one else is allowed access?

Is it like: iptables –A INPUT –s 128.238.66.2 –j ACCEPT?

Upvotes: 3

Views: 276

Answers (2)

Dev Anand Sadasivam
Dev Anand Sadasivam

Reputation: 763

When we say about iptable it is that it bounds with Kernel. The function of iptable is for Setting_Up Firewall.

And to understand its basics you should understand it in, from ground level rather knocking with your sequence of absurd commands as you end-up scribbling & scratching head. Following step by step standard instruction will not be scenario always. SO, lets understand it.

There are three level segregation when we talk about iptable.

Level-1: Rule

Level-2: Chain

Level-3: Table

Lets see one by one now,

Rules are-> ACCEPT, DROP, QUEUE, RETURN

Chains are-> Input, Output, Forward, Pre Routing, Post Routing

Tables are-> Filter Table (Default), NAT Table, RAW Table, Mangle Table

Coming Next Firewalls by generations of improvement can be said like,

1) Packet Filtering Firewall

2) Stateful Firewall

3) Application Layer Firewall

4) Proxies Firewall.

Upvotes: 1

Manuel Arwed Schmidt
Manuel Arwed Schmidt

Reputation: 3596

Try like this (please be aware that if the IP is wrong, you're locked out):

iptables -A INPUT -p tcp --dport ssh -j REJECT
iptables -A INPUT -p tcp -s 128.238.66.2 --dport ssh -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp --sport ssh -m state --state ESTABLISHED -j ACCEPT

Upvotes: 4

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