network security and threats

Question 1

what is a firewall

Answer 1

a firewall is a device designed to prevent unauthorised access to a network

firewall consists of two network interface cards (NICs) between the user and the Internet.

The firewall passes the packets between these two NICs and compares them against a set of rules set by the firewall software. The preconfigured rules are called packet filters

Question 2

packet filtering

Answer 2

one method firewalls use is packet filtering
-this checks details in a packet header such as it’s source and destination ip addresses , port number and the protocol it is running

Question 3

proxies

Answer 3

intermediaries between two devices communicating , collecting and sending data on behalf of the user.

Question 4

benefits of using proxies

Answer 4

• The privacy of the user is protected and they remain anonymous
• The proxy server can cache frequently used website data making it faster to load
• Proxies can reduce overall web traffic
• Can be used by administrators to prevent access to sensitive or irrelevant
  information at work or at school

Question 5

encryption

Answer 5

Encryption is a way of keeping data secure when transmitting it over the Internet. Encryption makes data unreadable if it is intercepted. Data is encrypted and decrypted using a set of keys.

Question 6

monitoring

Answer 6

can protect against the threat of hacking , can introduce malware

• can be used to protect against the threat of malware and hacking
• packet sniffers
• user access logins

Question 7

prevention

Answer 7

up to date patches to the operating system and application programs reduce vulnerabilities in the system

Question 8

threats

Answer 8

malware = hostile instrusive software (used in active attacks)

viruses = insert themselves in normal programs , so when the host program gets executed , so does the virus

worm = like viruses but spread autonomously , due to them spreading so quickly , they can overload networks

Question 9

threats

Answer 9

trojans = installed on a computer disguised as desirable software.

spyware - collects data about activities in the computer , then sends it back to the attack instigator

phishing = obtaining sensitive information by disguising
the message and link as a trustworthy source.can contain malware

an example of social engineering , which explains the fact that people often the weak points systems by manipulating them

Question 10

explain how the use of a proxy server may make access to websites for users

Answer 10

a proxy can maintain a cache of websites commonly visited and return the webpage data to the user immediately without reconnections to the internet.this speeds up access to websites

Question 11

describe the term firewall (exam question)

Answer 11

a hardware device that monitors packets going to and from a network

Question 12

state why the architect firm would use firewall (exam questions)

Answer 12

prevents unauthorised access to a network