Networking

Question 1

Explain the OSI model and the TCP/IP protocol stack.

Answer 1

• OSI model and the TCP/IP protocol stack are both frameworks that conceptualize network communication

Question 2

How does the OSI and TCP/UDP stack relate to each other

Answer 2

• the layers in both models can be correlated
• Application = Application, Presentation, and Session
• Internet = Network
• Transport = Transport
• Network Interface = Data, Physical

Question 3

What are the key differences between OSI model and TCP/UDP stack?

Answer 3

• they differ in their approach and layer organization.
• OSI is 7 layers (Application to Network)
• TCP/UDP is 4 layers (Network Interface, Internet, Transport, and Application)

Question 4

Describe the process of DNS resolution

Answer 4

DNS resolution is the process of translating human-readable domain names into IP addresses

Question 5

How does a web browser translate a domain name into an IP address

Answer 5

1. it sends a DNS query to the local DNS resolver
2. If the resolver doesn’t have the mapping cached, it contacts the authoritative name server responsible for the domain
3. authoritative server replies with the IP address
4. the resolver caches the result for future use
5. the resolver provides the IP address to the browser
6. the browser establishes a connection to the web server using the IP

Question 6

What is the purpose of subnetting in IP addressing?

Answer 6

• dividing a larger IP network into smaller, more manageable sub-networks or subnets
• aids in efficient network design by segmenting traffic, improving security, and optimizing resource usage
• helps in IP address allocation

Question 7

what are the benefits of using Variable Length Subnet Masks (VLSM)

Answer 7

• VLSM enables the allocation of different-sized subnets within a single network
• conserves IP address space
• accommodates varying subnet requirements

Question 8

Explain the differences between TCP and UDP

Answer 8

• TCP: connection-oriented and offers reliable, ordered, and error-checked data delivery
• UDP: connectionless and offers lightweight, low-latency communication

Question 9

When would you choose TCP or UDP?

Answer 9

• TCP for applications where data integrity is crucial
• UDP for applications where speed is prioritized over reliability

Question 10

Provide examples of applications that use TCP or UDP and justify your choices

Answer 10

• TCP: web browsing, file transfer (FTP), and email (SMTP)
• UDP: streaming media (UDP-based streaming services), online gaming (UDP minimizes latency for real-time interactions), WiFi authentication

Question 11

Discuss the concept of NAT (Network Address Translation)

Answer 11

NAT involves translating private IP addresses used within an internal network to a single public IP address for external communication

Question 12

What is the significance of NAT in modern networking

Answer 12

• helps conserve the limited pool of public IPv4 addresses
• enables multiple devices to share a single public IP
• NAT became a workaround to address the scarcity of IPv4 addresses

Question 13

what are the implications for NAT use and IPv4 address exhaustion and IPv6 adoption

Answer 13

• NAT poses challenges for direct peer-to-peer communication
• NAT complicates network configurations
• NAT hinders the deployment of IPv6 due to its widespread use
• IPv6 adoption is crucial to overcome address exhaustion

Question 14

What are some TCP benefits

Answer 14

1. Flow control
2. Error correction
3. Retransmission

Question 15

What does TLS provide?

Answer 15

Provides encryption and authenticity for TCP-based protocols

Question 16

How does TLS work?

Answer 16

Certs are verified by validating a certificate chain and that the hostname of the server matches the name in the certificate

Question 17

What do you need to do to get a certificate?

Answer 17

1. Have the Correct Website Information
2. Decide Which SSL Certificate You Need
3. Choose a Certificate Authority
4. Generate a Certificate Signing Request (CSR)
5. Submit the CSR to Your Certificate Authority
6. Await Validation by Your Certificate Authority
7. Install Your SSL Certificate

Question 18

How does a web browser determine a certificate is valid?

Answer 18

Browsers have a list of trusted Certificate Authorities (CAs) they use to validate the cert chain

Question 19

If a key is compromised, how do you revoke it?

Answer 19

1. The CA can revoke a certificate
2. Revocation data is published via:
   Certificate Revocation Lists or
   Online Cert Status Protocol