The Art of Doing: Master Networks and Network Scanning

Explore decimal, binary, and hexadecimal number systems and how place values determine a number's value. Apply these base concepts to IP addressing, net masks, and MAC addresses.

Define what an IP address is and distinguish private internal IPs from the public external address on a home network. Compare IPv4's four-octet dot-decimal notation with IPv6's eight groups.

Discover how net masks define the network and host IDs in IPv4. Convert between binary and dot-decimal notation and apply 255.255.255.0 (slash 24) to identify 254 hosts on a network.

Discover how ip addresses define a device location on a network and how mac addresses identify the device, with arp tables mapping the two.

Discover how address resolution protocol (ARP) links IP addresses to MAC addresses, builds an ARP table, and uses broadcast ARP requests and direct replies to enable device communication.

Configure virtual networks in VirtualBox by using NAT, bridged, and internal options to isolate or connect VMs, and learn to assign unique IP and MAC addresses.

Learn how to use ifconfig to view and manage network interfaces, bring them up or down, and set IP addresses, net masks, and broadcast, while noting the newer ip command.

Learn to use the IP command to view and manage IP addresses, interfaces, and MAC addresses, including IPv4 and IPv6, with show, grep, and awk.

Learn how ARP and ping reveal how IP addresses map to MAC addresses, manage ARP caches, flush tables, and perform address resolution using broadcast requests and direct pings.

Explore how ping uses ICMP to test connectivity, triggers ARP requests to resolve IP-to-MAC mappings, and reveals latency while examining the ARP cache, tcpdump, and practical ping options.

Write a bash script to scan a subnet by pinging sequential ip addresses, dynamically derive the network id, capture arp cache entries, and save results with grep and date stamps.

Learn to change or spoof a Mac address with Mac changer to hide your identity on a network, including random or specific addresses and known vendor lookups.

demonstrates using a USB wifi adapter to connect a Kali VM to a real network, enabling MAC address changes with macchanger and bridged adapter, highlighting Linux driver compatibility.

Explore how routing tables direct packets by matching destination IPs to network IDs, applying gateway rules and default routes, and using trace route to map hops.

Change and verify IP addresses with IP addr and IP route, set a default gateway, and observe routing behavior and ARP associations across devices.

Explain what happens when two devices share the same ip address, showing arp requests, mac address conflicts, and resulting connectivity loss; previews scripting a random mac and ip.

Write a bash script that randomizes a device's Mac and IP addresses for any device, including virtual and real adapters.

Explore how ports, protocols, and services route data to the right app using IP and MAC address mapping, with examples like FTP 21, SSH 22, HTTP 80, DNS 53.

Compare tcp and udp protocols, highlighting tcp's connection-oriented, reliable, ordered delivery with a three-way handshake, and udp's fast, connectionless, unordered transfer. See how these traits affect streaming, gaming, and dns.

Explore well-known services and their ports, and learn how client–server communication uses specific ports to route data, covering ftp, ssh, telnet, dns, dhcp, http, and https.

Inspect system services and their ports using /etc/services, lsof, and network connections; learn startup scripts in /etc/init.d and manage services, including installing and enabling vsftpd.

Start, restart, and stop the vsftpd server with systemctl, enable anonymous logins, transfer files with the ftp client, and verify connectivity.

Start and stop sshd with systemctl, verify port 22, and adjust sshd_config to permit root login. Demonstrate remote terminal access, file edits, process management, and exiting sessions across two machines.

Analyze network traffic with tcpdump to compare tcp and udp communications, visualize the three-way handshake, and observe send, push, and ack patterns between ssh and udp data flows.

Learn how to replace netstat with the ss command to view tcp and udp connections, identify established vs listening sockets, and monitor changes in real time with watch.

Develop and run a bash script that monitors tcp and udp traffic, detects status changes with ss, and alerts you via a popup window using zenity, enabling continuous monitoring.

Block unauthorized access by using firewalls to monitor network traffic, block specific ports or IPs, and apply IP tables rules that manage input, forward, and output chains.

Learn to use iptables on Linux to filter network traffic by blocking, accepting, or rejecting specific IP addresses, and manage input and output chains.

Block traffic using iptables by filtering specific ports and IP addresses on input and output chains, applying drop and reject actions, and testing connectivity.

Learn how to evade a firewall by changing the host IP address, adjust iptables rules for port 22, and explore basic networking and Linux commands.

Build a wall firewall script in kali linux using iptables to block all traffic by default and selectively allow selected ip addresses passed as arguments.

Use netcat to create a simple chat server over TCP or UDP by listening on a port. Connect from a client to exchange messages.

Master netcat port scanning by using -z for non-connecting scans, enabling verbose output to reveal open ports on another machine and infer running services such as http and ssh.

Explore netcat's ability to send scripts and commands across the network, scan for open ports, and reveal bind or reverse shell concepts.

Learn to use nmap for host discovery and port scanning, targeting domains, IPs, or ranges, and interpreting open ports, services, and mac addresses.

Explore nmap scanning techniques for host discovery and port probing, including ping, syn, connect, ack, and udp scans, with firewall filtering and port state (open, closed, filtered, unfiltered).

Learn how to use nmap for service classification and version detection on open ports. Discover OS detection and XML output to HTML reports for a clear network assessment.

The lecture demonstrates a comprehensive network scan with nmap, including host discovery and version and OS detection across a three-machine lab, with HTML report generation and iptables firewall testing.