Cybersecurity of Networks from Scratch to Advanced

Explore the ISO/OSI seven-layer open system interconnection model, its end-to-end data flow, layer responsibilities from physical to application, and vendor-interoperable protocols like TCP/IP, IPX/SPX, and Apple Talk.

Explore how the application, presentation, and session layers format data for reliable communication. They manage session setup, maintenance, and termination while supporting http, ftp, and smtp.

Explore how the transport layer delivers end-to-end data with reliability or best-effort, handling segmentation, sequencing, flow control, and loss recovery, while the network layer handles routing and IP addressing.

Explore the data link layer’s hop-by-hop reliability, physical addressing (MAC), frame creation, and error checking, plus the physical layer’s transmission of bitstreams across copper, fiber, or wireless.

Understand the seven ISO/OSI layers—application, presentation, session, transport, network, data link, and physical—as a framework for interoperable communication with standard protocols.

Explore computer network protocols, OSI to TCP/IP mappings, addressing and routing rules, and essential protocols like DNS, Telnet, FTP, and IP.

Explore how the IP protocol routes datagrams using addresses, subnet masks, and routing tables to deliver packets across networks, including public and private addresses.

Compare tcp and udp transport protocols, detailing sockets, port numbers, and session multiplexing, with tcp delivering reliable, connection-oriented delivery and udp offering best-effort, real-time data.

Survey application-layer protocols in the TCAP IP model, including DTP and its secure variant on port 443, FTP on 21, and DNS and DHCP for name resolution and IP leasing.

Master tcp/ip troubleshooting with ipconfig, ping, arp, nslookup, netstat, ftp, and route print to identify ip addresses, dns names, and active connections.

Explore the benefits of wireless networks over wired, including mobility, flexibility, scalability, and cost savings. Enable guest access, remote work, bring your own device, and expansion with access points.

Explore wireless network types and how frequency ranges, coverage area, bandwidth, distance, and speed distinguish wifi, Bluetooth, GPS, and WiMAX, with insights into licensed and unlicensed bands and regulatory roles.

Explore the wifi protocol and 802.11 standards, 2.4 and 5 gigahertz bands, channels and guard bands; compare infrastructure and ad hoc networks, ssid naming, and rts/cts collision avoidance.

Explore wireless network devices, from access points connecting mobile devices to wired infrastructure to web-based configuration, security, PoE, and the differences between wifi and gsm broadband.

Explore the drawbacks of wireless networks, including coverage limitations caused by walls, distances, and weather, as well as security risks like sniffing, costs, and the challenge of replacing wired infrastructure.

Understand the balance between access and security, and apply the CIA triad (confidentiality, integrity, and availability) to protect assets from threats, vulnerabilities, and exploits while assessing risk.

Design a secure network from the start by separating public, DMZ, and private zones, applying defense in depth with a firewall and ACLs to publish internet services while protecting assets.

Analyze ip header fields, protocols (icmp, tcp, udp), fragmentation and ttl behavior, nat and dmz isolation, and three-way and four-way handshakes, using N-Gage packet builder to craft tcap/ip packets.

Explore port scanning fundamentals and the use of Nmap and Zenmap to map networks, identify open ports and services, and assess potential vulnerabilities with permission.

Explore sniffing concepts, how professionals capture network data to diagnose issues and detect malicious traffic, and how tools like tcpdump and wireshark analyze packets.

Protect internal networks from external threats with a firewall that inspects traffic at the gateway and blocks unauthorized access. Consider limitations and layered defenses like honeypots and DMZs.

Understand how firewall rules decide to accept or reject packets, balancing default deny and default allow to protect against zero-day attacks, with incoming and outgoing traffic examples.

Explore how packet filtering, NAT, proxy, and stateful inspection firewalls classify traffic, compare speed and security, and illustrate personal and border protections for robust network defense.

Honeypots act as decoy systems, attracting attackers with fake services to collect forensics about their methods, IP addresses, and malware, enabling stronger network defense.

Identify how dynamic port use and peer-to-peer programs can bypass windows firewall and expose data across the network. Configure inbound and outbound rules, monitor protections, and balance access with security.

Define intrusion detection systems as host-based or network-based alarms that report attacks, not replacements for firewalls or patching. Highlight alerts, false positives, false negatives, and defense in depth.

Explore how network intrusion detection systems function as passive sensors at network aggregation points, using signature-based rules to alert on anomalous traffic patterns and protocol or payload anomalies.

Examine the main challenges of deploying network intrusion detection systems, including deployment and access limits, storage and processing constraints, encrypted traffic analysis, and deep versus shallow inspection tradeoffs.

Deploy Snort as a low-cost, lightweight intrusion detection system for monitoring multiple sites and sensors. Configure it to generate alerts with flexible reporting and a low false alarm rate.

Block attacks on networks and hosts with intrusion prevention systems that actively enforce policy. Learn normal traffic patterns in learning mode to reduce false positives and guide analyst decisions.

Analyze wired equivalent privacy (WEP) as a wireless encryption protocol, its shared secret keys, and the security risks of open wireless media.

WPA, introduced in 2003 as a successor to WEP, strengthens encryption and adds user authentication, while WPA2 (2004–2006) uses AES with CCMP for stronger, interoperable security and mitigates WEP vulnerabilities.

Identify and challenge wireless security misconceptions about sensitive data. Enforce defense in depth by isolating and encrypting wireless-to-wired traffic, detecting rogue access points, and guarding against spoofing and denial-of-service threats.

Explore common wireless attacks such as eavesdropping and rogue access points, and learn mitigation techniques including strong encryption, mutual authentication, firmware patching, and readiness planning.

Design a secure wireless network by segregating access points on a separate switch, enforcing firewall inspection, and auditing for rogue devices while monitoring encryption, channels, and access controls.

Protect personnel and property by enforcing physical security objectives that deny unauthorized access to buildings, equipment, and data, using surveillance, redundancy, and RAID to safeguard CIA confidentiality, integrity, and availability.

Detail physical security threats and mitigations, prioritizing human safety with sensors, alarms, signage, and access controls, and address fire, water flooding, temperature extremes, power loss, and escort procedures.

Apply defense in depth by layering security across information, application, host, and network, using encryption, access controls, and updated software to deter attackers and mitigate zero-day attacks.

Define events and incident handling by focusing on events of interest that signal potential attacks, such as scans, sendmail exploits, or missing backups, and determine cause and effect.

Prepare and plan incident handling with a published policy, assign a dedicated team, and establish disaster recovery and emergency communication plans to identify, contain, recover, and learn from security incidents.

Explore the CIA triad—confidentiality, integrity, and availability—and how access relies on something you know, something you have, and biometrics including fingerprint and voiceprint.

Identify and protect an organization’s assets by understanding threats and vulnerabilities, assessing how confidentiality, integrity, and availability are impacted, and minimizing risk through ongoing mitigation.

Minimize risk by evaluating threat, vulnerabilities, and impact using the risk formula threat × vulnerabilities × impact, and examine intrusion effects like identity theft and service disruption.

Identify common attacks in cyber and network security, including social engineering and phishing, viruses, worms, Trojan horses, denial of service, brute force, spyware, tracking cookies, and spam.

Identify malware propagation vectors—from removable media to email, web, social networks, and instant messaging—and implement strong security policies, up-to-date systems, firewalls, antivirus, and network isolation.