Introductory Networking : TryHackMe
An introduction to networking theory and basic networking tools
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.
- 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
- 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
- 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
- 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
- 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
- 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
- Perform a whois search on facebook.com
- 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
- 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 :)
