Aman Firewall

8/7/2019 Aman Firewall

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WeLCOME

SEMINAR ON FIREWALL

AMAN BHARDWAJ

B.Tech(CS) 4th SEM

ROLL NO.- 15


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Firewalls


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Firewalls

What is a Firewall

Types of Firewall Network Layer and Packet Filters

Application Layer

Proxy Firewalls

Network Address Translations


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What is a Firewall?

A hardware or software solution whichrestricts access between your network and

an outside network.

Firewall can be uni-directional or bi-directional Usually at perimeter (where the two networks meet)

Like a Military Checkpoint:

Stops all traffic in and/or out of your network

Inspects the traffic to see if it meets the security policy

Allows or denies the traffic based on the security

policy

Like a real checkpoint, it will slow down traffic!!!


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What is a Firewall

A firewall's function within a network is similar

to firewalls in building construction, because in

both cases they are intended to isolate one

"network" or "compartment" from another.However, network firewalls, unlike physical

firewalls, are designed to allow some traffic to

flow.


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What is a Firewall? A firewall :

Acts as a security gateway

between two networks

Usually between trusted

and untrusted networks

(such as between a

corporate network and

the Internet

Corporate

Site

Corporate

Site

Internet

Corporate Network

Gateway


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EVOLUTION OF FIREWALLS

Packet

Filter

Application

Proxy

Stateful

Inspection

Stage of Evolution


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Types of Firewall

There are mainly four types of Firewalls

Network layer and packet filters

Application-layer

Proxies

Network address translation


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Packet Filter

How Packet filters work

Read the header and filter by whether fields

match specific rules

The firewall administrator may define the rules; or

default rules may apply

Operate at network level, not application level


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Application-Layer

Application-layer firewalls work on theapplication level of the TCP/IP stack, and may

intercept all packets traveling to or from anapplication.

Stronger security

Harder to implement and maintain

Requires writing new or custom rules/proxies asapplications and protocols change or are introduced

Slower performance, less scalable


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Proxy firewalls

Proxy firewalls pass data between two

separate connections, one on each side of

the firewall.

Proxies should not route packets between

interfaces.


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Network Address Translation

(NAT)

NAT changes the ip addresses in a packet, so that

the address of the client inside never shows up on

the internet.

Examples: Cisco PIX, Linux Masquerading, Firewall

One, ipfilter


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Appropriate use of Firewalls

Firewalls are applicable when

When there is two networks that have a distinct

trust factor (friend/foe).

When protected networks connection must

terminate behind firewall.

When there is need for extra layer of protection

for certain applications.


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Configuration Considerations

By default, less trusted networks has NO access tothe trusted network (deny all).

Be port specific as possible when allowing outsidehost to access applications.

Rulesets/access-list will not work unless applied tointerface.

Certain applications are very firewall sensitive (i.e.Voice, H323)


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THANK YOU

Aman Firewall

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