Firewall New

7/31/2019 Firewall New

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Firewalls


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CONTENTS

l What is firewall

l Types of firewall

l What firewall protects us froml Firewall Limitations


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What is firewall ?

LANINTERNET

A firewall is simply a software orhardware device or a combination of

both that filters the information comingthrough the Internet connection intoyour private network and/or a single

computerActs as a security gateway between twonetworks


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Hardware Firewalls

Protect an entire network

Implemented on the routerlevel

Usually more expensive,harder to configure


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Software Firewalls

Protect a single computer

Usually less expensive

easier to configure

PC

Internet

Firew

all


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Popular hardware & softwarefirewalls

Software Firewall Hardware Firewall

Ms. ISA Server Cisco PIX

Norton Internet Security Blue Coat

Mcafee Internet Security Cyberoam

ZoneAlarm Check Point

Kerio NetScreen

BlackICE defender D-link SECURESPOT

Outpost WatchGuard


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TYPES OF FIREWALL


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Evolution of Firewalls

Packet

Filter

StatefulInspection

Stage of

Evolution

ApplicationProxy


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Packet Filters

l Very basic

l Also called Network Layer Firewalls

l Not allowing packets to pass through thefirewall unless they match theestablished ruleset.

l If it meets the regulations the firewalls

forwards it to the another networkotherwise discarded.


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ADVANTAGES AND DISADVANTAGE S OFPACKET FILTERS

Advantag

es:CheapDoes not affect the network performance

Disadvantages:Difficulty of setting up packet

filter rulesAllows direct connections to internal hosts byexternal clients Offers no user authentication


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Application levelgateway(Proxy server)

l Information from the Internet is retrievedby the firewall and then sent to the

requesting system and vice versa.l proxy servers sit between the client and

actual servier. Both the client and server

talk to the proxy rather than directly witheach other.

l The proxy server effectively hides thetrue network addresses.


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Advantages:

Higher security than packet filters Blocks on content, not just URL

Easy to log and audit all incoming traffic Direct connections between internal and

external hosts are disallowed. User-level authentication is supported.


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Disadvantages

ExpensiveSlower than packet filters

Affecting network performanceRequires modification to client software

application

Some protocols arent supported by proxyservers

Some proxy servers may be difficult toconfigure and may not provide all the

protection you need.


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Stateful Multilayer Inspection Firewall

A newer method that doesn't examine thecontents of each packet but insteadcompares certain key parts of the packet

to a database of trusted information. stateful packet inspection as it maintains

records of all connections passing through

the firewall and is able to determine packetis valid or not


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qMost secure firewall

DISADVANTAGES

qExpensiveqMust be set up byprofessional

ADVANTAGES


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What firewall protects usfrom

n Remote login

n Application backdoors

n SMTP session hijacking

n Operating system bugs

n Denial of servicen E-mail bombs

n Viruses

n SPAMs

n Trojans

n ICMP bombing


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l just because you have a firewall, dont believe you arefully protected against malware

l cannot protect against transfer of all virus infectedprograms or files

l After setting it initially, you can forget about it The firewall will require periodic updates to the

rulesets and the software itself

l Cannot prevent e-mail viruses

Only an antivirus product with updated definitions canprevent e-mail viruses

Firewall Limitations


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Thankyou

Documents

Firewall New