Firewallpresentation 100826052003-phpapp02(1)

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PRESENTERS :-

VARUN SACHDEVA ABHISHEK

KHYATI MATHUR

PRABHDEEP KAUR

Presentation :’Firewalls’

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Introduction

FireWall is device that provides secure connectivity between networks..

A firewall may be a hardware, software, or a combination of both that is used to prevent unauthorized programs or Internet users from accessing a private network and/or a single computer.

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Hardware vs. Software Firewalls

Hardware Firewalls Protect an entire network Implemented on the router level Usually more expensive, harder to configure

Software Firewalls Protect a single computer Usually less expensive, easier to configure

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How does a software firewall work?

Inspects each individual “packet” of data as it arrives at either side of the firewall

Determines whether it should be allowed to pass through or if it should be blocked

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Types of Firewalls

Common types of Firewalls:

1. Packet-filtering routers2. Application-level gateways13. Circuit-level gateways1

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◦Packet-filtering Router

• Applies a set of rules to each incoming IP packet and then forwards or discards the packet

◦Filter packets going in both directions◦The packet filter is typically set up as a list of

rules based on matches to fields in the IP or TCP header

◦Two default policies (discard or forward)

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Packet Filtering Firewall

Trusted Network

Firewall rule set

Packet is Blocked or Discarded

Untrusted Network

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Packet Filtering Firewall

A packet filtering firewall is often called a network layer firewall because the filtering is primarily done at the network layer (layer three) or the transport layer (layer four) of the OSI reference model.

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Application-level Gateway

Gateway sits between user on inside and server on outside. Instead of talking directly, user and server talk through proxy.

Allows more fine grained and sophisticated control than packet filtering. For example, ftp server may not allow files greater than a set size.

A mail server is an example of an application gateway◦ Can’t deposit mail in recipient’s mail server without passing

through sender’s mail server

host-to-gatewayftp session

gateway-to-remote host ftp session

applicationgateway

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Application Gateways/Proxies

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Circuit-level Gateway

1. Stand-alone system 2. Specialized function performed by an Application-level

Gateway3. Sets up two TCP connections4. The security function consists of determining which

connections will be allowed5. Typically use is a situation in which the system administrator

trusts the internal users

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Circuit-level Gateway

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Firewall Rules

Allow – traffic that flows automatically because it has been deemed

Block – traffic that is blocked because it has been deemed dangerous to your computer

Ask – asks the user whether or not the traffic is allowed to pass through

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Making The Firewall Fit

IP address

Domain names

Protocols

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What It Protects You From

Remote login

Simple Mail Transfer Protocol session hijacking

Operating system bugs

Spam

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Conclusion

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What a personal firewall can do ?

• Stop hackers from accessing your computer.

• Protects your personal information.

• Blocks “pop up” ads and certain cookies.

• Determines which programs can access the Internet.

• Block invalid packets.

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• What a personal firewall cannot do ?

• Cannot prevent e-mail

viruses– Only an antivirus product

with updated definitions can

prevent e-mail viruses.

• After setting it initially, you cannot forget about it– The firewall will require periodic updates to the rulesets

and the software itself.

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Thank you