Network Security: Cyber Security [From Zero to Advanced]

The OSI model visualizes seven layers, from the physical layer with bits to the transport layer, showing how a frame becomes a packet at a router and a firewall policy.

Explore how the physical layer converts data into bits over copper and fiber, compare straight-through and crossover Ethernet cables, and explain TX/RX pairs and auto detection.

This lecture covers the data link layer, where traffic becomes a frame, explains the llc and mac sublayers, and highlights mac addresses, switches, and ip versus mac forwarding.

Learn how switches use a mac address table to forward frames, flooding to all devices until the destination mac is learned, then unicasting via learned port, with a five-minute cooldown.

Explore how switches learn MAC addresses dynamically or statically, and how VLANs create separate networks, using access and trunk ports to control broadcast traffic.

Explain how ARP resolves IP addresses to MAC addresses in a local area network by querying the ARP table cache, and distinguish dynamic versus static mappings.

This lecture explains the network layer with IP addresses and subnets, and shows how a packet travels from computer A to computer B via routers and routing tables.

Learn the basics of networking, including IP addresses, subnets, routes, and how routers determine where to send traffic, with a hands-on look at bits and bytes.

Explore how subnet masks define usable host ranges and broadcast addresses using real topology examples, learning to assign network, host, and router addresses with /30 and /22 prefixes.

Explore the transport layer in the OSI model and its link to stateful inspection, firewall concepts, and perimeter versus host-based security.

Learn how static routes and routing tables determine next hops across a three-network topology, including directly connected networks and default gateways, with practical CLI and graphical setup.

Explore network address translation (nat) and its types, including many-to-one nat, static nat, and port forwarding, with practical examples of external and internal interfaces and port mapping.

Demonstrate how traffic travels from Bob to Alice across two subnets, detailing IP addressing, MAC addresses, frames, and the transition from data link to transport layers.

Explore where a firewall sits in the OSI model, between the data link (layer 2) and network (layer 3), operating on IP addresses and ports to block or allow traffic.

Explore HTTP and HTTPS fundamentals, including URL structure, ports 80 and 443, firewall considerations, and how TLS/SSL uses server certificates, public keys, and session keys to secure communication.

Learn how the domain name system uses a dns server to map website names to ip addresses, enabling access and latency benefits, while operating at layer seven alongside firewalls.

Explore how DHCP automates IP address assignment using a DHCP server, providing IP address, subnet mask, default gateway, and DNS, with automatic allocation versus manual configuration in the application layer.

Explore the capabilities of next generation firewalls, including firewall policies, URL filtering, application control, VPN site-to-site and remote access, antivirus, and IPS with zero-day protection and sandboxing.

Examine how stateful inspection firewalls use a connection table to track TCP sessions, enabling one-rule setup and secure FTP traffic while blocking unexpected or out-of-state packets.

Explore how modern firewalls with modules like VPN, application control, and IPS inspect traffic near the internet to enforce Active Directory–based group policies and block vulnerabilities.

Explore IPS attack and protection techniques within network security and cyber security. See practical examples from zero to advanced concepts.

Learn the front and back panels of a firewall appliance, including transceiver slots, patch ports, sync, management, console, USB, lights-out, and power for clustering and remote access.

Deploy a firewall as a virtual machine or appliance, noting acceleration differences, and ensure it can handle traffic without CPU maxing out to avoid drops.

Explore clustering and redundancy to ensure network availability and security through automatic failover and load sharing, with virtual cluster IPs and VRRP.

Define virtual private networks and explain how they provide availability to a resource through a secure tunnel, using authentication, data integrity, data confidentiality, and encryption.

Learn the core vpn terms, including IPsec, vpn peers, external IP addresses, and encryption domains, and see how traffic from defined subnets travels through a secure tunnel.

compare IPsec and ssl vpn protocols, noting IPsec supports both client-to-site and site-to-site, while ssl is client-only; IPsec encrypts up to the transport layer, ssl encrypts all layers.

Explore the fundamentals and differences of virtual private networks, focusing on side-to-side and client side configurations, topology, encryption domains, and how VPNs secure and enable access over the internet.

Explore how to route encrypted vpn traffic across simple, star, and full mesh topologies, including hub-and-spoke configurations, encryption domains, and central device roles.

Establishes an IPsec tunnel between site a (1921681.0) and site b (172.6.2.0) with matching phase 1 and 2 settings, encrypting traffic at the firewall and decrypting on the remote device.

Explore security association concepts, detailing phase one and phase two parameters, such as authentication method, local encryption, hashing, and encryption, and contrast GUI configurations with the established VPN assays.

Explore ipsec phases 1 and 2, including ike main mode, external peer ip addresses, encryption domains, diffie-hellman key exchange, and how hashes, authentication, and lifetime shape secure tunnels.

Compare IPsec main mode and aggressive mode, detailing packet flows, six packets in main mode and three in aggressive mode, secure key exchange, and when each is preferred.

IPsec main mode encrypts phase one for stronger security, slowing traffic. Aggressive mode uses fewer packets, is faster, and can work with ip or fqdns using pre-shared secret or certificates.

Detect and manage dead peers with dead period detection (DPD) by sending keepalive packets and awaiting ack to keep vpn tunnels alive, using on-demand, on-idle, or disabled modes across vendors.

Explore perfect forward secrecy in ipsec, comparing enabling versus disabling pfs across phase one and two, using diffie-hellman and shared secrets.

Compare ipsec tunnel mode and transport mode, explaining that tunnel mode encrypts the original IP header and data with ESP, prepends an outer IP header, and trades security for throughput.

Explore remote access vpn traffic flow from client connection to internal site, detailing phase one ike, phase two sa, config mode, and virtual adapter ip, dns, and static route setup.

Learn how sandboxing pairs with a next-gen firewall to trap zero-day threats, using virtual machines to analyze suspicious files and block them based on behavior verdicts.

Explore sandboxing behind a next-generation firewall with IPS and antivirus to detect zero-day threats by routing suspicious files to a sandbox and issuing a verdict.