Introductory Networking : TryHackMe

An introduction to networking theory and basic networking tools

https://tryhackme.com/room/introtonetworking

Task 1 : Introduction

The topics that we’re going to cover in this room are:

  • The OSI Model
  • The TCP/IP Model
  • How these models look in practice
  • An introduction to basic networking tools

Task 2 : The OSI Model: An Overview

The OSI (Open Systems Interconnection) Model is a standardised model which we use to demonstrate the theory behind computer networking.

  1. Which layer would choose to send data over TCP or UDP?

Ans: 4

2. Which layer checks received packets to make sure that they haven't been corrupted?

Ans: 2

3. In which layer would data be formatted in preparation for transmission?

Ans: 2

4. Which layer transmits and receives data?

Ans: 1

5. Which layer encrypts, compresses, or otherwise transforms the initial data to give it a standardised format?

Ans: 6

6 . Which layer tracks communications between the host and receiving computers?

Ans: 5

7. Which layer accepts communication requests from applications?

Ans: 7

8. Which layer handles logical addressing?

Ans: 3

9. When sending data over TCP, what would you call the "bite-sized" pieces of data?

Ans: TCP — Segments / UDP — Datagrams

10. [Research] Which layer would the FTP protocol communicate with?

Ans: 4

11. Which transport layer protocol would be best suited to transmit a live video?

Ans : UDP

TCP would usually be chosen for situations where accuracy is favoured over speed (e.g. file transfer, or loading a webpage), and UDP would be used in situations where speed is more important (e.g. video streaming).

Task 3: Encapsulation

  1. How would you refer to data at layer 2 of the encapsulation process (with the OSI model)?

Ans : Frames

In layers 7,6 and 5, the data is simply referred to as data. In the transport layer the encapsulated data is referred to as a segment or a datagram. Network Layer, the data is referred to as a packet. When the packet gets passed down to the Data Link layer it becomes a frame, and by the time it’s transmitted across a network the frame has been broken down into bits.

2. How would you refer to data at layer 4 of the encapsulation process (with the OSI model), if the UDP protocol has been selected?

Ans : Datagrams

3. What process would a computer perform on a received message?

Ans : De-encapsulation

4. Which is the only layer of the OSI model to add a trailer during encapsulation?

Ans : Data Link

5. Does encapsulation provide an extra layer of security (Aye/Nay)?

Ans : Aye

Task 4 : The TCP/IP Model

  1. Which model was introduced first, OSI or TCP/IP?

Ans : TCP/IP

2.Which layer of the TCP/IP model covers the functionality of the Transport layer of the OSI model (Full Name)?

Ans : Transport

3. Which layer of the TCP/IP model covers the functionality of the Session layer of the OSI model (Full Name)?

Ans : Application

4. The Network Interface layer of the TCP/IP model covers the functionality of two layers in the OSI model. These layers are Data Link, and?.. (Full Name)?

Ans : Physical

5. Which layer of the TCP/IP model handles the functionality of the OSI network layer?

Ans : Internet

6. What kind of protocol is TCP?

Ans : Connection-based

7. What is SYN short for?

Ans : Synchronise

8.What is the second step of the three way handshake?

Ans : SYN/ACK

9. What is the short name for the “Acknowledgement” segment in the three-way handshake?

Ans : ACK

Task 5 : Wireshark

  1. What is the protocol specified in the section of the request that’s linked to the Application layer of the OSI and TCP/IP Models?

Ans : Domain Name System

2. Which layer of the OSI model does the section that shows the IP address “172.16.16.77” link to (Name of the layer)?

Ans : Network

3. In the section of the request that links to the Transport layer of the OSI and TCP/IP models, which protocol is specified?

Ans : user datagram protocol

4. Over what medium has this request been made (linked to the Data Link layer of the OSI model)?

Ans : Ethernet II

5. Which layer of the OSI model does the section that shows the number of bytes transferred (81) link to?

Ans : Physical

6. [Research] Can you figure out what kind of address is shown in the layer linked to the Data Link layer of the OSI model?

Ans : MAC

Task 6 : [Networking Tools] Ping

  1. What command would you use to ping the bbc.co.uk website?

Ans : ping bbc.co.uk

2. Ping muirlandoracle.co.uk
What is the IP address?

Ans : 217.160.0.152

3. What switch lets you change the interval of sent ping requests?

Ans : -i

4. What switch would allow you to restrict requests to IPV4?

Ans : -4

5. What switch would give you a more verbose output?

Ans : -v

Task 7 : [Networking Tools] Traceroute

  1. Use traceroute on tryhackme.com
    Can you see the path your request has taken?

Ans :No Ans. Needed

2. What switch would you use to specify an interface when using Traceroute?

Ans : -i

3. What switch would you use if you wanted to use TCP requests when tracing the route?

Ans : -t

4. [Lateral Thinking] Which layer of the TCP/IP model will traceroute run on by default?

Ans : Internet

Task 8 : [Networking Tools] WHOIS

  1. Perform a whois search on facebook.com
  2. Ans : No Ans. Needed

2. What is the registrant postal code for facebook.com?

Ans : 94025

3. When was the facebook.com domain first registered?

Ans : 29/03/1997

4. Perform a whois search on microsoft.com

Ans : No Ans. Needed

5. Which city is the registrant based in?

Ans : Redmond

6. [OSINT] What is the name of the golf course that is near the registrant address for microsoft.com?

Ans : Bellevue Golf Course

7. What is the registered Tech Email for microsoft.com?

Ans : msnhst@microsoft.com

Task 9 : [Networking Tools] Dig

  1. What is DNS short for?

Ans : Domain Name System

2. What is the first type of DNS server your computer would query when you search for a domain?

Ans : Recursive

3. What type of DNS server contains records specific to domain extensions (i.e. .com, .co.uk, etc)? Use the long version of the name.

Ans : Top-level Domain

4. Where is the very first place your computer would look to find the IP address of a domain?

Ans : Local Cache

5. [Research] Google runs two public DNS servers. One of them can be queried with the IP 8.8.8.8, what is the IP address of the other one?

Ans : 8.8.4.4

6. If a DNS query has a TTL of 24 hours, what number would the dig query show?

Ans : 86400

TTL is given in seconds. The typical default value is usually 12 hours (43200 seconds) or 24 hours (86400 seconds). For example — a website moves to a new server; or, you add a new URL to your server. It takes 12–24 hours for the new DNS changes to take effect.

Thank you :)

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