Network Security Firewalls hELPFUL TT.ppt

Network Security Firewalls
Network Security Firewalls
Prepared by
Prepared by : Kh Mustafizur Rahman
Lecturer, Dept. Of CSE, WUB .
World University of Bangladesh.

Outline of Presentation
Outline of Presentation
 The Nature of Today’s Attacker
The Nature of Today’s Attacker
 Firewall Definition and History
Firewall Definition and History
 What Firewalls Do and Cannot Do
What Firewalls Do and Cannot Do
 Types of Firewalls
Types of Firewalls
 Firewall Architecture
Firewall Architecture
 Do You Need a Firewall
Do You Need a Firewall
 Selecting Firewall
Selecting Firewall
 Implementations
Implementations
 Conclusion
Conclusion

The Nature of Today’s Attackers
The Nature of Today’s Attackers
 Who are these “hackers” who are trying to break into your
computer?
Most people imagine someone at a keyboard late at night,
guessing passwords to steal confidential data from a computer
system.
This type of attack does happen, but it makes up a very small
portion of the total network attacks that occur.
Today, worms and viruses initiate the vast majority of attacks.
Worms and viruses generally find their targets randomly.
As a result, even organizations with little or no confidential
information need firewalls to protect their networks from these
automated attackers.

What Is a Firewall?
 The term firewall has been around for quite some time and originally was
used to define a barrier constructed to prevent the spread of fire from
one part of a building or structure to another. Network firewalls provide
a barrier between networks that prevents or denies unwanted or
unauthorized traffic.
 Definition: A Network Firewall is a system or group of systems used to
control access between two networks -- a trusted network and an
untrusted network -- using pre-configured rules or filters.

What Is a Firewall?
 Device that provides secure connectivity between networks
(internal/external; varying levels of trust)
 Used to implement and enforce a security policy for
communication between networks
 Firewalls can either be hardware and/or software based.

Firewalls History
Firewalls History
 Firewall technology emerged in the late 1980s when the Internet
was a fairly new technology in terms of its global use and
connectivity. The original idea was formed in response to a
number of major internet security breaches, which occurred in
the late 1980s.

Firewalls History
Firewalls History
 First generation - packet filters
First generation - packet filters
The first paper published on firewall technology was in 1988,
The first paper published on firewall technology was in 1988,
when Jeff Mogul from Digital Equipment Corporatin (DEC)
when Jeff Mogul from Digital Equipment Corporatin (DEC)
developed filter systems known as packet filter firewalls.
developed filter systems known as packet filter firewalls.
 Second generation - circuit level
Second generation - circuit level
From 1980-1990 two colleagues from AT&T Company, developed
From 1980-1990 two colleagues from AT&T Company, developed
the second generation of firewalls known as circuit level
the second generation of firewalls known as circuit level
firewalls.
firewalls.
 Third generation - application layer
Third generation - application layer
Publications by Gene Spafford of Purdue University, Bill Cheswick
Publications by Gene Spafford of Purdue University, Bill Cheswick
at AT&T Laboratories described a third generation firewall. also
at AT&T Laboratories described a third generation firewall. also
known as
known as proxy based
proxy based firewalls.
firewalls.

Firewalls History
History
 Subsequent generations
In 1992, Bob Braden and Annette DeSchon at the University of
Southren California (USC) were developing their own fourth
generation packet filter firewall system.
In 1994 an Israeli company called Check Point Software
Technologies built this into readily available software known as
FireWall-1.
Cisco, one of the largest internet security companies in the world
released their PIX ” Private Internet EXchange ” product to the
public in 1997.

What Firewalls Do
What Firewalls Do
 Positive Effects
Positive Effects
 Negative Effects
Negative Effects

What Firewalls Do
What Firewalls Do (
(Positive Effects
Positive Effects)
)
Positive Effects
Positive Effects
 User authentication.
Firewalls can be configured to require user authentication. This
allows network administrators to control ,track specific user
activity.
 Auditing and logging.
By configuring a firewall to log and audit activity, information
may be kept and analyzed at a later date.

What Firewalls Do
What Firewalls Do (
(Positive Effects
Positive Effects)
)
 Anti-Spoofing - Detecting when the source of the network traffic is
being "spoofed", i.e., when an individual attempting to access a
blocked service alters the source address in the message so that
the traffic is allowed.
 Network Address Translation (NAT) - Changing the network
addresses of devices on any side of the firewall to hide their true
addresses from devices on other sides. There are two ways NAT is
performed:
– One-to-One - where each true address is translated to a unique
translated address.
– Many-to-One - where all true addresses are translated to a
single address, usually that of the firewall.

What Firewalls Do
What Firewalls Do (
(Positive Effects
Positive Effects)
)
 Virtual Private Networks
VPNs are communications sessions traversing public networks
that have been made virtually private through the use of
encryption technology. VPN sessions are defined by creating a
firewall rule that requires encryption for any session that meets
specific criteria.

What Firewalls Do
What Firewalls Do (
(Negative Effects
Negative Effects)
)
 Negative Effects
Negative Effects
Although firewall solutions provide many benefits, negative
Although firewall solutions provide many benefits, negative
effects may also be experienced.
effects may also be experienced.
– Traffic bottlenecks.
Traffic bottlenecks. By forcing all network traffic to pass
By forcing all network traffic to pass
through the firewall, there is a greater chance that the
through the firewall, there is a greater chance that the
network will become congested.
network will become congested.
– Single point of failure.
Single point of failure. In most configurations where
In most configurations where
firewalls are the only link between networks, if they are not
firewalls are the only link between networks, if they are not
configured correctly or are unavailable, no traffic will be
configured correctly or are unavailable, no traffic will be
allowed through.
allowed through.

What Firewalls Do
What Firewalls Do (
(Negative Effects
Negative Effects)
)
– Increased management responsibilities.
Increased management responsibilities. A firewall often
A firewall often
adds to network management responsibilities and makes
adds to network management responsibilities and makes
network troubleshooting more complex.
network troubleshooting more complex.

What Firewalls Cannot Do
 The most common misconception about firewalls is that they
The most common misconception about firewalls is that they
guarantee security for your network.
guarantee security for your network.
 A firewall
A firewall cannot and does not
cannot and does not guarantee that your network is
guarantee that your network is
100% secure.
100% secure.
 Firewalls cannot offer any protection against inside attacks. A
Firewalls cannot offer any protection against inside attacks. A
high percentage of security incidents today come from inside the
high percentage of security incidents today come from inside the
trusted network.
trusted network.

 In most implementations, firewalls cannot provide protection
In most implementations, firewalls cannot provide protection
against viruses or malicious code. Since most firewalls do not
against viruses or malicious code. Since most firewalls do not
inspect the payload or content of the packet, they are not aware
inspect the payload or content of the packet, they are not aware
of any threat that may be contained inside.
of any threat that may be contained inside.
 Finally, no firewall can protect against inadequate or
Finally, no firewall can protect against inadequate or
mismanaged policies.
mismanaged policies.

How Firewalls Work
How Firewalls Work
 There are two security design logic approaches network firewalls
use to make access control decisions.
– Everything not specifically permitted is denied.
– Everything not specifically denied is permitted.
 The one most often recommended is everything not specifically
permitted is denied.

How Firewalls Work
How Firewalls Work
 Basic TCP/IP Flow review
Basic TCP/IP Flow review

Types of Firewalls
 Firewalls types can be categorized depending on:
– The Function or methodology the firewall use
– Whether the communication is being done between a single
node and the network, or between two or more networks.
– Whether the communication state is being tracked at the
firewall or not.

Types of Firewalls
1. By the Firewalls
1. By the Firewalls methodology :
:
 Packet Filtering
Packet Filtering
 Stateful Packet Inspection
Stateful Packet Inspection
 Application Gateways/Proxies
Application Gateways/Proxies
 Adaptive Proxies
Adaptive Proxies
 Circuit Level Gateway
Circuit Level Gateway

Packet Filtering Firewall
A packet filtering firewall does exactly what its name implies -- it
filters packets.
As each packet passes through the firewall, it is examined and
information contained in the header is compared to a pre-
configured set of rules or filters. An allow or deny decision is
made based on the results of the comparison. Each packet is
examined individually without regard to other packets that are
part of the same connection.

Trusted
Network
Firewall
rule set
Packet is Blocked or Discarded
Untrusted
Network

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

You use packet filters to instruct a firewall to drop traffic that
You use packet filters to instruct a firewall to drop traffic that
meets certain criteria.
meets certain criteria.
For example, you could create a filter that would drop all ping
For example, you could create a filter that would drop all ping
requests. You can also configure filters with more complex
requests. You can also configure filters with more complex
exceptions to a rule.
exceptions to a rule.

Packet filtering rules or filters can be configured to allow or deny
Packet filtering rules or filters can be configured to allow or deny
traffic based on one or more of the following variables:
traffic based on one or more of the following variables:
– Source IP address
Source IP address
– Destination IP address
Destination IP address
– Protocol type (TCP/UDP)
Protocol type (TCP/UDP)
– Source port
Source port
– Destination port
Destination port

Packet Filtering
Strengths :
Strengths :
 Packet filtering is typically
Packet filtering is typically faster than other packet screening
than other packet screening
methods. Because packet filtering is done at the lower levels of the
methods. Because packet filtering is done at the lower levels of the
OSI model, the time it takes to process a packet is much quicker.
OSI model, the time it takes to process a packet is much quicker.
 Packet filtering firewalls can be
Packet filtering firewalls can be implemented transparently
implemented transparently. They
. They
typically require no additional configuration for clients.
typically require no additional configuration for clients.
 Packet filtering firewalls are typically
Packet filtering firewalls are typically less expensive
less expensive. Many
. Many
hardware devices and software packages have packet filtering
hardware devices and software packages have packet filtering
features included as part of their standard package.
features included as part of their standard package.

Packet Filtering
Weaknesses
 Packet filtering firewalls allow a direct connection to be made
between the two endpoints. Although this type of packet screening
is configured to allow or deny traffic between two networks, the
client/server model is never broken.
 Packet filtering firewalls are fast and typically have no impact on
network performance, but it's usually an all-or-nothing approach. If
ports are open, they are open to all traffic passing through that
port, which in effect leaves a security hole in your network.
 Defining rules and filters on a packet filtering firewall can be a
complex task.

Packet Filtering (Weaknesses)
 Packet filtering firewalls are prone to certain types of attacks.
Since packet inspection goes no deeper than the packet header
information, There are three common exploits to which packet
filtering firewalls are susceptible.
– These are IP spoofing
sending your data and faking a source address that the
firewall will trust
– ICMP ”Internet Control Message Protocol” tunneling
ICMP tunneling allows a hacker to insert data into a
legitimate ICMP packet.

 Stateful packet inspection uses the same fundamental packet
Stateful packet inspection uses the same fundamental packet
screening technique that packet filtering does. In addition, it
screening technique that packet filtering does. In addition, it
examines the packet header information from the network layer
examines the packet header information from the network layer
of the OSI model to the application layer to verify that the packet
of the OSI model to the application layer to verify that the packet
is part of a legitimate connection and the protocols are behaving
is part of a legitimate connection and the protocols are behaving
as expected.
as expected.

Stateful Packet Inspection Firewall
As packets pass through the firewall, packet header information
is examined and fed into a dynamic state table where it is stored.
The packets are compared to pre-configured rules or filters and
allow or deny decisions are made based on the results of the
comparison.
The data in the state table is then used to evaluate subsequent
packets to verify that they are part of the same connection.

This method can make decisions based on one or more of the following:
 Source IP address
 Destination IP address
 Protocol type (TCP/UDP)
 Source port
 Destination port
 Connection state

 The connection state is derived from information gathered in previous
packets.
 It is an essential factor in making the decision for new communication
attempts.
 Stateful packet inspection compares the packets against the rules or
filters and then checks the dynamic state table to verify that the packets
are part of a valid, established connection.
 By having the ability to "remember" the status of a connection, this
method of packet screening is better equipped to guard against attacks
than standard packet filtering.

Trusted
Network
Packet is Blocked or Discarded
Untrusted
Network

Strengths :
Strengths :
 Like packet filtering firewalls, have very little impact on network
Like packet filtering firewalls, have very little impact on network
performance.
performance.
 More secure than basic packet filtering firewalls. Because stateful packet
More secure than basic packet filtering firewalls. Because stateful packet
inspection digs deeper into the packet header information to determine
inspection digs deeper into the packet header information to determine
the connection state between endpoints.
the connection state between endpoints.
 Usually it have some logging capabilities. Logging can help identify and
Usually it have some logging capabilities. Logging can help identify and
track the different types of traffic that pass though the firewall.
track the different types of traffic that pass though the firewall.

Weaknesses
 Like packet filtering, stateful packet inspection does not break the
client/server model and therefore allows a direct connection to be made
between the two endpoints
 Rules and filters in this packet screening method can become complex,
hard to manage, prone to error and difficult to test.

 The proxy plays middleman in all connection attempts.
 The application gateway/proxy acts as an intermediary between the two
endpoints. This packet screening method actually breaks the client/server
model in that two connections are required: one from the source to the
gateway/proxy and one from the gateway/proxy to the destination. Each
endpoint can only communicate with the other by going through the
gateway/proxy.

 This type of firewall operates at the application level of the OSI model.
For source and destination endpoints to be able to communicate with
each other, a proxy service must be implemented for each application
protocol.
 The gateways/proxies are carefully designed to be reliable and secure
because they are the only connection point between the two networks.

Firewall
Firewall
 When a client issues a request from the untrusted network, a connection
When a client issues a request from the untrusted network, a connection
is established with the application gateway/proxy. The proxy determines
is established with the application gateway/proxy. The proxy determines
if the request is valid (by comparing it to any rules or filters) and then
if the request is valid (by comparing it to any rules or filters) and then
sends a new request on behalf of the client to the destination. By using
sends a new request on behalf of the client to the destination. By using
this method, a direct connection is never made from the trusted network
this method, a direct connection is never made from the trusted network
to the untrusted network and the request appears to have originated
to the untrusted network and the request appears to have originated
from the application gateway/proxy.
from the application gateway/proxy.
Untrusted
Network
Application
Gateway (Proxy
service)
Work
Station

Firewall
Firewall
 The response is sent back to the application gateway/proxy, which
The response is sent back to the application gateway/proxy, which
determines if it is valid and then sends it on to the client.
determines if it is valid and then sends it on to the client.
 By breaking the client/server model, this type of firewall can effectively
By breaking the client/server model, this type of firewall can effectively
hide the trusted network from the untrusted network.
hide the trusted network from the untrusted network.
 It is important to note that the application gateway/proxy actually builds
It is important to note that the application gateway/proxy actually builds
a new request, only copying known acceptable commands before
a new request, only copying known acceptable commands before
sending it on to the destination.
sending it on to the destination.
 Unlike packet filtering and stateful packet inspection, an application
Unlike packet filtering and stateful packet inspection, an application
gateway/proxy can see all aspects of the application layer so it can look
gateway/proxy can see all aspects of the application layer so it can look
for more specific pieces of information
for more specific pieces of information

Strengths
 Application gateways/proxies do not allow a direct connection to be
made between endpoints. They actually break the client/server model.
 Typically have the best content filtering capabilities. Since they have the
ability to examine the payload of the packet, they are capable of making
decisions based on content.
 Allow the network administrator to have more control over traffic passing
through the firewall. They can permit or deny specific applications or
specific features of an application.

Weaknesses
Weaknesses
 The most significant weakness is the impact they can have on
The most significant weakness is the impact they can have on
performance.
performance.
it requires more processing power and has the potential to become a
it requires more processing power and has the potential to become a
bottleneck for the network.
bottleneck for the network.
 Typically require additional client configuration. Clients on the network
Typically require additional client configuration. Clients on the network
may require specialized software or configuration changes to be able to
may require specialized software or configuration changes to be able to
connect to the application gateway/proxy.
connect to the application gateway/proxy.

Adaptive Proxies
Adaptive Proxies
 Known as dynamic proxies
Known as dynamic proxies
 Developed as an enhanced form of application gateways/proxies.
Developed as an enhanced form of application gateways/proxies.
Combining the merits of both application gateways/proxies and packet
Combining the merits of both application gateways/proxies and packet
filtering
filtering

Circuit-level Gateway
Circuit-level Gateway
 Unlike a packet filtering firewall, a circuit-level gateway does not examine
Unlike a packet filtering firewall, a circuit-level gateway does not examine
individual packets. Instead, circuit-level gateways monitor TCP or UDP
individual packets. Instead, circuit-level gateways monitor TCP or UDP
sessions.
sessions.
Once a session has been established, it leaves the port open to allow all
Once a session has been established, it leaves the port open to allow all
other packets belonging to that session to pass. The port is closed when
other packets belonging to that session to pass. The port is closed when
the session is terminated.
the session is terminated.
circuit-level gateways operate at the transport layer (layer 4) of the OSI
circuit-level gateways operate at the transport layer (layer 4) of the OSI
model.
model.

Types of Firewalls
2.
2. With regard to the scope of filtered communications the done
With regard to the scope of filtered communications the done
between a single node and the network, or between two or more
between a single node and the network, or between two or more
networks there exist :
networks there exist :
– Personal Firewalls, a software application which normally filters traffic entering
or leaving a single computer.
– Network firewalls, normally running on a dedicated network device or
computer positioned on the boundary of two or more networks.

Types of Firewalls
3. Finally, Types depending on whether the firewalls keeps track of the
state of network connections or treats each packet in isolation, two
additional categories of firewalls exist:
– Stateful firewall
– Stateless firewall

Types of Firewalls
Stateful firewall
keeps track of the state of network connections (such as TCP
keeps track of the state of network connections (such as TCP
streams) traveling across it.
streams) traveling across it.
Stateful firewall is able to hold in memory significant attributes of
Stateful firewall is able to hold in memory significant attributes of
each connection, from start to finish. These attributes, which are
each connection, from start to finish. These attributes, which are
collectively known as the state of the connection, may include such
collectively known as the state of the connection, may include such
details as the IP addresses and ports involved in the connection and
details as the IP addresses and ports involved in the connection and
the sequence numbers of the packets traversing the connection.
the sequence numbers of the packets traversing the connection.

Types of Firewalls
Stateless firewall
Treats each network frame (Packet) in isolation. Such a firewall has no
Treats each network frame (Packet) in isolation. Such a firewall has no
way of knowing if any given packet is part of an existing connection,
way of knowing if any given packet is part of an existing connection,
is trying to establish a new connection, or is just a rogue packet.
is trying to establish a new connection, or is just a rogue packet.
The classic example is the File Transfer Protocol, because by design it
The classic example is the File Transfer Protocol, because by design it
opens new connections to random ports.
opens new connections to random ports.

Firewall Architecture
 Since firewall solutions can be configured using a single system or
multiple systems, the architecture used to implement the solution can be
simple or complex.
– Packet Filtering Router
– Screened Host (Bastion Host)
Screened Host (Bastion Host)
– Dual-homed Gateway
Dual-homed Gateway
– Screened Subnet or Demilitarized Zone (DMZ)
Screened Subnet or Demilitarized Zone (DMZ)
– Firewall Appliance
Firewall Appliance

Packet Filtering Router
Packet Filtering Router
 A packet filtering router is a router configured to screen packets between
A packet filtering router is a router configured to screen packets between
two networks. It routes traffic between the two networks and uses packet
two networks. It routes traffic between the two networks and uses packet
filtering rules to permit or deny traffic.
filtering rules to permit or deny traffic.
Trusted
Network
Untrusted
Network
Filtering Router

Screened Host (Bastion Host)
 Router provides packet filters for some basic services
 Bastion host proxies more risky services
 Not suitable for exporting services

Dual-homed Gateway
Dual-homed Gateway
 A dual-homed gateway firewall consists of a highly secured host system
A dual-homed gateway firewall consists of a highly secured host system
running proxy software It has two network interfaces, one on each side
running proxy software It has two network interfaces, one on each side
of the firewall . Only gateways or proxies for the services that are
of the firewall . Only gateways or proxies for the services that are
considered essential are installed on the system.
considered essential are installed on the system.

Screened Subnet or Demilitarized
Screened Subnet or Demilitarized
Zone (DMZ)
Zone (DMZ)
 Created between two packet filtering routers.
Created between two packet filtering routers.
 The exterior router is the only connection between the enterprise network and the
The exterior router is the only connection between the enterprise network and the
outside world
outside world
 The interior router does the bulk of the access control work. It filters packets
The interior router does the bulk of the access control work. It filters packets
 The bastion host is a secure server. It provides an interconnection point between
The bastion host is a secure server. It provides an interconnection point between
the enterprise network and the outside world for the restricted services
the enterprise network and the outside world for the restricted services
 The perimeter network connects the servers together and connects the exterior
The perimeter network connects the servers together and connects the exterior
router to the interior router
router to the interior router

Do you need a firewall
?
?
 The decision to implement a firewall solution should not be made without
The decision to implement a firewall solution should not be made without
doing some research and analysis.
doing some research and analysis.
 What does the firewall need to control or protect?
What does the firewall need to control or protect?
In order to make a sound decision, first identify what functions the
firewall would need to perform. Will it control access to and from the
network, or will it protect services and users?
– What would the firewall control?
 Access into the network
 Access out of the network
 Access between internal networks, departments, or buildings
 Access for specific groups, users or addresses
 Access to specific resources or services

?
?
 What would it need to protect?
– Specific machines or networks
– Specific services
– Information - private or public
– Users

?
?
 What impact will a firewall have on your organization,
network and users?
– What resources will be required to implement and maintain a firewall solution?
– Who will do the work? Are experienced technical personnel available for the
job or will someone need to be hired from outside your organization?
– Is hardware available that meets the requirements to support a firewall
solution?
– Will existing services be able to function through a firewall?
– What will the financial impact be on the organization? (Financial impact should
include initial implementation costs, ongoing maintenance and upgrades,
hardware and software costs, and technical support costs, whether the
support is provided in-house or from an outside source.)

Selecting Firewall Solution
Selecting Firewall Solution
In order to pick the best architecture and packet screening method
In order to pick the best architecture and packet screening method
for a firewall solution, the following questions should
for a firewall solution, the following questions should be considered:
be considered:
 What does the firewall need to do?
What does the firewall need to do?
 What additional services would be desirable?
What additional services would be desirable?
 How will it fit in the existing network?
How will it fit in the existing network?
 How will it effect existing services and users?
How will it effect existing services and users?

Security Policy
Security Policy
The success of any firewall solution's implementation is directly related to
The success of any firewall solution's implementation is directly related to
the existence of a well-thought-out and consistently-implemented
the existence of a well-thought-out and consistently-implemented
security policy.
security policy.
Some of the topics a security policy may address are:
Some of the topics a security policy may address are:
 Administrative Issues
Administrative Issues
– User access - Which users will be allowed access to and from the network?
User access - Which users will be allowed access to and from the network?
– Access to services - Which services will be allowed in and out of the network?
Access to services - Which services will be allowed in and out of the network?
– Access to resources - Which resources will be available to users?
Access to resources - Which resources will be available to users?
– User authentication - Will the organization require user authentication?
User authentication - Will the organization require user authentication?
– Logging and auditing - Will the organization want to keep log and audit files.
Logging and auditing - Will the organization want to keep log and audit files.
– Policy violation consequences - What will be the consequences of policy
Policy violation consequences - What will be the consequences of policy
violation?
violation?
– Responsibilities - Who will oversee and administer the security policy? Who has
Responsibilities - Who will oversee and administer the security policy? Who has
final authority on decisions?
final authority on decisions?

Security Policy
Security Policy
 Technical Issues
Technical Issues
– Remote access - Will the organization allow remote access to the network?
Remote access - Will the organization allow remote access to the network?
– Physical security - How will physical security of machines, one of the most
Physical security - How will physical security of machines, one of the most
obvious security elements that is often overlooked, be achieve?
obvious security elements that is often overlooked, be achieve?
– Virus protection - How will the organization handle virus protection?
Virus protection - How will the organization handle virus protection?

Implementations
Implementations
 Software
Software
– Devil-Linux
Devil-Linux
– Dotdefender
Dotdefender
– ipfirewall
ipfirewall
– PF
PF
– Symantec
Symantec …
…
 Hardware
– Cisco PIX
– DataPower
– SofaWare Technologies

Conclusion
Conclusion
 Don’t make the mistake of thinking that no one will attack your network,
Don’t make the mistake of thinking that no one will attack your network,
because with the rise in automated attack tools, your network is as much
because with the rise in automated attack tools, your network is as much
at risk as every other network on the Internet.
at risk as every other network on the Internet.
 The need for firewalls has led to their ubiquity. Nearly every organization
The need for firewalls has led to their ubiquity. Nearly every organization
connected to the Internet has installed some sort of firewall.
connected to the Internet has installed some sort of firewall.
 When choosing and implementing a firewall solution, make a decision
When choosing and implementing a firewall solution, make a decision
based on the organization's needs, security policy, technical analysis, and
based on the organization's needs, security policy, technical analysis, and
financial resources. Solutions available today utilize different types of
financial resources. Solutions available today utilize different types of
equipment, network configurations, and software.
equipment, network configurations, and software.

Q & A
Q & A
Questions ?
Questions ?

Network Security Firewalls hELPFUL TT.ppt

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Network Security Firewalls hELPFUL TT.ppt

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