PRESENTED BY:
R. SRINIVASULU
CH. SHIVA RAM
K. MALLIKARJUNA
V. SUMAN KUMAR REDDY

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A MAIN PROJECT SEMINAR ON PACKET FILTERING FIREWALL USING NETFILTERS IN LINUX FOR ARM9
Aim of the project:
Network Security is a huge concern for enterprise networks.
Firewall is a machine which sits between public and private networks and block traffic based on configurable rules.
Linux kernel provides a mechanism to implement our own firewall using NETFILTERS.
So using this feasibility of Linux we create our own firewall and make it to block packets belonging to different protocols according to our commands.
Block Diagram of Project
Essentials of the project
The main components of the project are
ARM9 Processor.
Linux Operating System.
Firewall Module.
Internet(LAN/WAN/MAN).
ARM9 Processor Features
ARM stands for Advanced RISC Machine.
It is a 32 bit RISC microprocessor.
In 2005 about 98% of one billion total mobile phones sold contains ARM processor.
Offers very high performance with less power consumption.
The main features of ARM9 are:
5 stage pipeline .
Processor speed- 250 MHz
Harvard architecture
156 MIPS
Cache memory- 16KB
Supports Windows CE, Symbian OS, Linux, Palm OS and Android
Arm9 applications
Consumer Electronics
Networking
Automotives
Embedded
Why Linux???
Linux is freely distributable open source operating system.
It is Portable.
Follows monolithic kernel architecture.
Runs on most of the processors even on ARM.
Scalable, can run on super computer and also tiny devices.
Excellent Networking support.
Computer network
A Network is a series of points or nodes interconnected by communication paths.
There are 7 layers proposed by ISO and named as OSI/ISO reference layer. They are namely Physical, Data link, Network, Transport, Session, Presentation, Application.
Networks can be classified on the basis of spatial distances. They are
LAN
MAN
WAN
There are many protocols on which network operate few are TCP/IP, ICMP, HTTP etc.
On internet, the network breaks a message into parts of a certain size in bytes. These are called packets.
These packets consist of Sender’s IP address and Destination’s IP address.
All these packets travel through routers, switches, bridges, gateways which operate at respective layers.
Need for Security
When a device is connected to a network and begins communicating with it, it is taking a risk.
Network security is generally taken as providing protection at the boundaries of an organization by keeping out intruders.
Information Security focuses on protecting sensitive data from malware attacks using Data Loss Prevention(DLP) techniques.
Firewalls are used to provide the security to a system.
A firewall is a part of a computer system(OS) or network that is designed to block unauthorized access while permitting authorized communications.
A firewall’s basic task is to regulate some of the flow of traffic between computer networks of different trust levels.
What is packet filtering??
Packet filters act by inspecting the “packets” which represent the basic unit of data transfer between computers on the internet.
If a packet matches the packet filter’s set of rules, the packet filter will drop or reject the packet.
A packet filtering firewall examines the header of packet, to determine source, destination and type of protocol.
Packet filtering firewalls work on the first three layers of OSI reference model.
Packet filters follow a set of pre-defined or user defined rules and decide which packet to drop an which packet to accept.
If a rule is something like “drop all HTTP traffic” then all packets with HTTP header are dropped.
How does the project works???
In our project we insert the firewall into Linux kernel and run it on ARM9 board.
The actions such as Accept, Drop are to be taken with respect to the user defined rules based on
a) Protocol Type
b) IP address
c) Port numbers
First we assign a ip address and default gateway to our board and connect it in LAN.
If we wish to block the ICMP packets then the command can be given as
“./user_arm_firewall --protocol icmp”
When this command is executed our firewall gets activated and no icmp packets will be transferred or it can be regarded as icmp packets are dropped.
The same way we can implement on other protocols, port numbers ip addresses etc.
Advantages and Applications
Basic level security can be provided efficiently.
User can configure the rules to his choice.
Time management helps user to run firewall at his choice of time.
The power requirement of ARM processor is low.
This project uses Linux which gives flexibility to implement our own firewall.
Firewall is applied any system where basic security is concerned.
Provides complete action of user choice to select particular packets.
Time based applications are also been achieved to specify the activation of packets for the respective time periods.
Future scope
Firewall can be extended over applications like
Maintaining statistics of number of packets dropped/accepted.
Storage of dropped packets for future use.
It can be designed in such a way that it gets activated on its own for the time it is scheduled to.
conclusion
Packets are filtered by firewall using net filters and the basic security is been achieved using the firewall.
Linux kernel provides a mechanism to implement our own firewall. This mechanism is called "Netfilters".
Hence Packet filtering using Net filters can successfully be implemented on an ARM processor.
The firewall developed is free of cost and also provides the basic level of security.
Netfilters firewall can drop packets based on protocols like http, icmp and based on source and destination ip address, port numbers.
Hence the user can configure and derive many more applications.