This document discusses network security through firewalls. It begins by outlining desirable network features such as high bandwidth, security, and low client costs. It then describes different levels of security from the BIOS to the application level. Common security issues like packet sniffing and password attacks are examined. The document defines a firewall as software that controls and analyzes data passing between networks, placed at the connection point between two networks. It classifies firewalls and discusses how dual-homed gateways can be set up. The document explores how firewalls provide protection against threats like remote logins, backdoors, session hijacking, and denial of service attacks. It concludes by stating that firewalls are a solution to common network security problems

1. 11
Network Security ThroughNetwork Security Through
FIREWALLFIREWALL
Presented By :-Presented By :-
Creativedev.inCreativedev.in

2. 22
Desirable feature of NetworkDesirable feature of Network
• High Bandwidth at low costHigh Bandwidth at low cost
• SECURITYSECURITY
• Low cost hardware and software at theLow cost hardware and software at the
client sideclient side

3. 33
Hierarchy of variousHierarchy of various
SECURITY levelsSECURITY levels
• BIOS level SecurityBIOS level Security
• Operating System level SecurityOperating System level Security
• Network Operating System SecurityNetwork Operating System Security
• Security Based upon IP addressSecurity Based upon IP address
• E-application SecurityE-application Security

4. 44
SECURITY Issues whileSECURITY Issues while
connecting on the Internetconnecting on the Internet
• Protect confidential informationProtect confidential information
– Network Packet SniffersNetwork Packet Sniffers
– IP SpoofingIP Spoofing
– Password AttacksPassword Attacks
– Man-in-the-middle AttacksMan-in-the-middle Attacks
– Application Layer AttacksApplication Layer Attacks

5. 55
About FIREWALLAbout FIREWALL
• ““A FIREWALL is a software, which is usedA FIREWALL is a software, which is used
for controlling and analyzing data passingfor controlling and analyzing data passing
between two networks.”between two networks.”
• Placed at the point of connection betweenPlaced at the point of connection between
two networkstwo networks
• Barrier to keep destructive forces awayBarrier to keep destructive forces away

6. 66

7. 77
FIREWALL ClassificationFIREWALL Classification
• Packet Filter Firewall (Stateless Inspection)Packet Filter Firewall (Stateless Inspection)
• Application Proxy FirewallApplication Proxy Firewall
• Stateful Packet filtering FirewallStateful Packet filtering Firewall
• Packet filtering based upon contentPacket filtering based upon content
• Network Address TranslationNetwork Address Translation

8. 88
Setup of FIREWALLSetup of FIREWALL
• Dual-homed gatewayDual-homed gateway

9. 99
Protection by FIREWALLProtection by FIREWALL
• Remote loginRemote login
• Application BackdoorsApplication Backdoors
• SMTP session hijackingSMTP session hijacking
• Operating System BugsOperating System Bugs
• Denial of ServiceDenial of Service
• DNS SpoofingDNS Spoofing

10. 1010
Protection by FIREWALLProtection by FIREWALL
• E-mail bombsE-mail bombs
• MacrosMacros
• VirusVirus
• SpamSpam
• Redirect bombsRedirect bombs
• Source RoutingSource Routing

11. 1111
Beyond FIREWALLS…Beyond FIREWALLS…
• VPNVPN
– A method of achieving security by use ofA method of achieving security by use of
software techniquessoftware techniques
– Use of unsecured public network likeUse of unsecured public network like
internet to transmit the data.internet to transmit the data.
• IPSecIPSec
– is a collection of protocols (by IETF )is a collection of protocols (by IETF )
– two modes are usedtwo modes are used
• Tunnel modeTunnel mode
• Transport modeTransport mode

12. 1212
Network Security UtilitiesNetwork Security Utilities
offered by popular O.S. vendorsoffered by popular O.S. vendors
• iptables and ipchains utilities in LINUX foriptables and ipchains utilities in LINUX for
FIREWALL configurationFIREWALL configuration
• Advanced stateful packet and application-Advanced stateful packet and application-
layer inspection firewall including VPN inlayer inspection firewall including VPN in
Microsoft Internet Security and ccelerationMicrosoft Internet Security and cceleration
(ISA) Server 2004(ISA) Server 2004

13. 1313
ConclusionConclusion
• With explosive growth of Internet to ‘always on’With explosive growth of Internet to ‘always on’
connectivity, security has become a concern toconnectivity, security has become a concern to
network administrators and individuals.network administrators and individuals.
• Even organizations without having anyEven organizations without having any
confidential information can find themselves toconfidential information can find themselves to
be victimized, which can result in loss/damage ofbe victimized, which can result in loss/damage of
services/equipment.services/equipment.
• To explore some of most common networkTo explore some of most common network
security problems, suggested possible solutionsecurity problems, suggested possible solution
is FIREWALL.is FIREWALL.

14. 1414
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