Firewall and Proxy Servers

7/29/2019 Firewall and Proxy Servers

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Name: N.Rajeeva11B91D4006


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Firewall Proxy Server Relationship between Proxy Server and

Firewall Types of Firewalls Hardware requirements Software requirements

Conclusion


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A computer firewall is a router or othercommunications device which filters access to aprotected network.

Firewall is also a program that screens allincoming traffic and protects the network fromunwelcome intruders.


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Firewalls can also be used as access controlmeasures to only allow certain people within theorganization access to the Internet. Many firewallsnow contain features to control, authenticate and

secure users who may want to access a companyinternal data from the Internet or even anothercompany.


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Proxy Server is a computer programthat acts as an intermediary betweena web browser and a web server. Togive users rapid access to popularweb destinations


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Part of an overall Firewall strategy Sits between the local network and the external network

Originally used primarily as a caching strategy to minimizeoutgoing URL requests and increase perceived browserperformance

Primary mission is now to insure anonymity of internal users Still used for caching of frequently requested files

Also used for content filtering

Acts as a go-between, submitting your requests to theexternal network

Requests are translated from your IP address to the Proxys IPaddress

E-mail addresses of internal users are removed from requestheaders

Cause an actual break in the flow of communications


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Internet Service Providers use proxy servers as"holding bins" to store frequently requested pages,rather than going out and fetching themrepeatedly from the Net

Proxy server is also used to control and monitoroutbound traffic


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Proxy Server is associated with firewall and alsocaching program

The functions of proxy, firewall, and caching can

be in separate server programs or combined in asingle package.

Proxy Server can be installed in the firewall toget a kind of proxy firewall


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Packet Filtering Firewalls

Proxy Server Firewalls


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Application Proxy

SOCKS Proxy


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As you telnet to the outside world the clientsend you to the proxy first. The proxy then

connects to the server you requested (theoutside world) and returns the data to you


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SOCKS is networking proxy protocol thatenables hosts on one side of a SOCKS server togain full access to hosts on the other side of theSOCKS server without requiring direct IP

reachability. SOCKS redirects connectionrequests from hosts on opposite sides of aSOCKS server. The SOCKS server authenticatesand authorizes the requests, establishes a proxy

connection, and relays data


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Filtering firewalls don't require fancy hardware.They are little more then simple routers a 486-DX66 with 32 meg of memory a 250m hard disk (500

recommended) network connections (LAN Cards,

Serial Ports, Wireless?) monitor and keyboard


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If you need a proxy server firewall to handle lotsof traffic, you should get the largest system youcan afford a Pentium II with 64meg of memory a two gig hard disk to store all the

logs two network connections monitor and keyboard


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To create a filtering firewall, you don't need anyspecial software. Linux will do

The built-in Linux firewall has changed severaltimes, for the newer 2.4 kernel there is a newfirewall utility with more features


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If you want to setup a proxy server you will needone of these packages

Squid

The TIS (Trusted InformationSystem) Firewall Toolkit (FWTK)

SOCKS


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Squid is a great package and works withLinux's Proxy feature


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The TIS Internet Firewall Toolkit is a set ofprograms and configuration practices

designed to facilitate the building ofnetwork firewalls.

The toolkit software is designed to run on

UNIX systems


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SOCKS can be installed both in NTsystem and UNIX system

RFC 1928 Not a true application layer proxy

SOCKS protocol provides a framework

for developing secure communicationsby easily integrating other securitytechnologies


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SOCKS includes two components SOCKS server

implemented at the application layer

SOCKS client

implemented between the application and transportlayers

The basic purpose of the protocol is toenable hosts on one side of a SOCKS server

to gain access to hosts on the other side ofa SOCKS Server, without requiring direct IP-reachability.


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Both firewall and proxy server are usedfor net work security and facility

Proxy server can be a part of firewall

Documents

Firewall and Proxy Servers