2. Firewall
A firewall is a network security system, in the form of computer
hardware or software, that monitors and controls incoming and
outgoing network traffic, based on predetermined security rules
It monitors attempts to gain access to your operating system and
blocks unwanted incoming traffic and unrecognized sources
It can also help block malicious software from infecting your
computer
A firewall typically establishes a barrier between a trusted network
and an untrusted network, such as the internet
3. How does firewalls work?
A firewall maintains a set of rules which are applied to both incoming
and outgoing traffic
It matches the traffic against those rules, and if the rules are matched,
it initiates the access
For outgoing traffic originating from the server,the firewall lets them
pass mostly
But for incoming traffic reaching from major protocol, the firewalls
monitor them strictly
4. The firewall inspects incoming traffic based on their:
1. Source
2. Content
3. Destination
4. Port
The firewall uses this data to decide whether the traffic abides by the
set rules
If yes,then it permits;otherwise, the traffic gets blocked by the firewall
6. A firewall acts as a gatekeeper
It monitors attempts to gain access to your operating system and
blocks unwanted traffic or unrecognized sources
A firewall acts as a barrier or filter between our computer and
another network such as the internet
It helps to protect our network and information by managing our
network traffic by blocking unsolicited incoming network traffic
and validating access by accessing network traffic for anything
malicious like hackers and malware
Any data which enters or exits a computer network has to pass
through the firewall
7. All the valuable information stays intact if the data packets are
securely passed through the firewall
Every time a data packet passes through a firewall, it records it
which allows the user to record the network activity
Precisely,a firewall ensures that all the data is secure and any
malicious data trying to enter the internal network is not allowed
to pass through
8. Firewall Techniques
There are four general techniques that firewall use to control
access and enforce the site’s security policy
Service control
Direction control
User control
Behavior control
9. Types of Firewall
Structurally firewall can be classified into
1. Software firewalls
2. Hardware firewalls
Firewalls are also categorized based on how they operate
1. Packet-filtering firewalls
2. Circuit level gateways
3. Stateful multi-layer inspection(SMLI) firewalls
4. Application -level gateways (proxy firewalls)
10. Risk of not having firewall
Cyber threats are widespread and evolving. It’s important to use available defense to help
protect your network, and the personal information stored on your computer, against
cybercrimes. Here are the three main risks of not having firewall:
Open access
Without a firewall, you’re accepting every connection into your network from anyone. You
wouldn’t have any way to detect incoming threats that could leave your device vulnerable
to malicious user
Lost or compromised data
Not having a firewall could leave your device exposed, which could allow someone to gain
control over your computer or network. Cybercriminals could delete your data.Or they
could use it to commit identity theft or financial fraud
Network crashes
Without a firewall, attackers could shut down your network. Getting it running again, and
attempting to recover your stored data, could involve your time and money
11. Limitations of Firewall
How it verifies trusted data
Our computer’s operating system have a list of trusted programs and
previously allowed programs. When data packet arrives a firewall, the
firewall checks whether the incoming data packet belongs to an
application in the list of reputed0 programs. If it belongs firewall allows
the data packet to pass through the computer. Hacker can easily exploit
this by creating a fake data packet containing trusted IP address to hack
our computer or our computer network
Insider’s intrusion
The firewall may not protect fully against internal threats, such as a
disgruntled employee or an employee who unwittingly cooperates with
an external hacker
12. Direct internet traffic
While installing an application like m Torrent in your
computer, during its installation you will get a check box
saying “Add an exception for m Torrent from internet to your
computer. In such cases hacker can send some malicious
data through m Torrent without being detected by the
firewall
13. Firewall’s trust on trusted network
Suppose your computer is connected to a network and your network is
connected to another trusted network via a hardware firewall, since
network is trusted firewall allows all the data packets coming from the
trusted network. If the hacker has connected his computer to this
trusted network firewall will allow all the infected data packets from
hacker to pass through your network and then to your computer
Firewalls do not provides us any antivirus or anti -malware
property
We need additional protection in our computer if some harmful files
have been introduced to our system from the networking channels like
emails
14. Antivirus software
Antivirus software typically uses two different techniques
to accomplish mission:
Examining (scanning) files to look for known viruses
matching definitions in a virus dictionary
Identifying suspicious behavior from any computer
program which might indicate infection. Such
analysis may include data captures, port monitoring
and other methods.
Antivirus software consists of computer programs that
attempt to identify, thwart and eliminate computer viruses
and other malicious software (malware).
15. Advantages of antivirus Software
Spam and advertisements are blocked
Virus protection and transmission prevention
Hackers and data thieves are thwarted
Protection against devices that can be detached
To improve security from web,restrict website access
Password protection
