TryHackMe Introductory Networking Writeup

Introduction to TryHackMe Introductory Networking

Networking is a critical aspect of cybersecurity and IT infrastructure. TryHackMe offers a great platform for learning about networking through interactive labs and hands-on exercises. This write-up aims to provide a comprehensive overview of the introductory networking room on TryHackMe, covering key concepts, commands, and lessons learned.

Please watch the video at the bottom for full detailed explanation of the walkthrough.

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Basic Networking Concepts

To understand how devices communicate over a network, it’s essential to grasp some foundational terms:

• IP Addressing: An IP address is a unique identifier assigned to each device connected to a network. There are two types of IP addresses:
• IPv4: A 32-bit address written in decimal format, e.g., 192.168.1.1.
• IPv6: A 128-bit address written in hexadecimal format, e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334.
• MAC Address: A Media Access Control address is a hardware identifier assigned to the network interface card (NIC). It’s unique to each device’s network interface.
• Subnetting: Subnetting divides a network into smaller, manageable segments or subnets, improving performance and security. A subnet mask (e.g., 255.255.255.0) determines which part of the IP address represents the network and which part represents the host.
• Packets: Data sent over a network is broken into smaller chunks called packets. Each packet contains the source and destination IP addresses, along with the data payload.

OSI Model

The OSI (Open Systems Interconnection) model is a framework that describes how data is transmitted over a network in seven layers:

1. Physical Layer: The physical connection between devices (cables, switches).
2. Data Link Layer: Responsible for MAC addresses and error detection in data frames.
3. Network Layer: Manages IP addresses and routing of packets.
4. Transport Layer: Ensures reliable data transfer (TCP/UDP).
5. Session Layer: Manages communication sessions.
6. Presentation Layer: Translates data formats (encryption, compression).
7. Application Layer: Interfaces with end-user applications (HTTP, FTP).

Common Networking Tools

During the TryHackMe tasks, you’ll be introduced to various networking tools that help troubleshoot and understand the network:

• ping: Used to check connectivity between devices. It sends an ICMP echo request and waits for a reply.
• Example: ping 8.8.8.8 (pings Google’s public DNS server).
• traceroute (or tracert): Shows the path a packet takes to reach its destination, listing all routers (hops) along the way.
• Example: traceroute 8.8.8.8 (or tracert on Windows).
• ipconfig/ifconfig: Displays network configuration details on your system, such as IP address, default gateway, and subnet mask.
• On Windows: ipconfig
• On Linux: ifconfig
• netstat: Displays active connections, listening ports, and routing tables.
• Example: netstat -an
• nslookup: Queries DNS servers to resolve domain names into IP addresses.
• Example: nslookup google.com

TCP/IP Model

While the OSI model provides a theoretical framework, the TCP/IP model is the practical implementation used on the internet. It has four layers:

1. Network Interface: Handles hardware connections (similar to the OSI Physical/Data Link Layers).
2. Internet: Routes packets using IP addresses (similar to OSI Network Layer).
3. Transport: Manages data transfer between devices (TCP/UDP, like OSI Transport Layer).
4. Application: Provides network services to end-users (HTTP, DNS, FTP, similar to OSI Application Layer).

Common Networking Protocols

In TryHackMe’s networking exercises, you’ll encounter various protocols:

• HTTP/HTTPS: Protocols used for transferring web pages.
• DNS (Domain Name System): Translates domain names into IP addresses.
• TCP (Transmission Control Protocol): Provides reliable, ordered data transmission.
• UDP (User Datagram Protocol): Allows faster, but less reliable, data transmission.
• DHCP (Dynamic Host Configuration Protocol): Automatically assigns IP addresses to devices.

Practical Exercise Walkthrough

In the TryHackMe introductory networking room, you’ll perform hands-on exercises to solidify your understanding. Here’s a general overview of the tasks:

1. IP Addressing and Subnetting: You’ll identify and calculate IP addresses and subnets to understand how networks are organized.
2. Using ping and traceroute: You will use these commands to test connectivity between devices and see the route data takes through a network.
3. Inspecting Packets: Using tools like Wireshark, you’ll capture and analyze packets traveling through a network.

Understanding Ports and Services

Ports are used to differentiate services running on a device. For example, web servers typically use port 80 for HTTP and port 443 for HTTPS. During the TryHackMe tasks, you’ll learn to identify open ports on a system using tools like Nmap.

• Nmap: A powerful network scanning tool that helps in identifying devices, open ports, and services running on a network.
• Example: nmap -sV 192.168.1.1 (scans a target for open ports and service versions).

Practical Example: Network Troubleshooting

One task might involve troubleshooting connectivity issues. Let’s break down a typical troubleshooting process using the tools and concepts you’ve learned:

• Step 1: Use ping to check connectivity between your machine and the target.
• Step 2: If ping fails, use traceroute to identify where the connection breaks down.
• Step 3: Run ipconfig (Windows) or ifconfig (Linux) to check your machine’s network configuration.
• Step 4: Use nslookup to resolve domain names to IP addresses if DNS issues are suspected.
• Step 5: Inspect open ports using netstat or scan with Nmap to identify which services are running on the network.

Key Takeaways

Understanding networking basics is essential for anyone looking to delve into cybersecurity or IT infrastructure.

Hands-on tools like ping, traceroute, and Nmap give you direct insights into how networks function and help troubleshoot connectivity issues.

TryHackMe’s labs provide a practical environment to apply networking concepts and troubleshoot real-world scenarios.

Room Answers | TryHackMe Introductory Networking

Room answers can be found here.

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