Learning Network Technology and Security

Explore tcp versus udp at the transport layer, detailing connection oriented delivery with a three way handshake and guaranteed delivery, versus connectionless, best effort delivery, ports 0–1023 and ephemeral ranges.

Identify Windows and Linux IP configurations, including MAC and IPv4 details. Explore IPv6 basics: hex notation, zero compression, and key ranges.

Review IPv4 address space to distinguish private ranges 10.x, 172.16.x, and 192.168.x from public addresses, and explain ARP at layer 2 using MAC addresses, including ARP cache poisoning risk.

Assess transmission media by efficiency and security, from fiber optic cables with photons and no emanations to coaxial and twisted-pair cables, down to wireless, the least secure but cheapest.

Explore attenuation and interference in network media, including impedance, insertion loss, cross-talk, and how EMI, RFI, and transient noise threaten data transmission and security.

Explore baseband versus broadband media and how time division and frequency or wavelength division multiplexing enable signals. Review Ethernet, token ring, Arcnet, and fiber optics with efficiency and cost tradeoffs.

Learn how twisted pair Ethernet cables work, including unshielded and shielded types, RJ-45 connectors, grounding, cat 1–6 speeds, and crossover cables shaping data rates and safety.

Explore wireless media transmission using the IEEE 802.11 wireless LAN standard, FCC allocations, modulation, and access points that enable roaming and secure connections to a wired core network.

Explore modulation and encoding at the physical layer, covering digital unipolar and bipolar signaling, analog schemes like AM, FM, PSK, and QAM for wireless and Ethernet media.

Explore intranets, extranets, and the internet, examining boundaries of administration, trust, and security devices, then compare pan, lan, man, wan, and global area networks.

Explore unicast, broadcast, multicast, and anycast transmission types. Learn how IP and MAC addresses, subnets, and IGMP enable one-to-one, one-to-many, and nearest-available delivery.

Analyze how a router connects segments and a bridge reduces traffic by splitting a segment into collision domains. Note how subnets like 192.168.10.0/24 enable logical separation on the physical segment.

Define a network segment and its boundary devices. Explain how routers, bridges, and switches divide collision and broadcast domains, and how subnets and sockets define addressing and services.

Bridges create two collision domains within a segment while preserving a broadcast domain, using MAC address tables to forward frames; switches replace hubs with layer 2 filtering and improved security.

Learn how layer 3 routers connect subnetworks, configure static routes with route -p add, and compare dynamic routing protocols like RIP and OSPF, including how metrics prevent routing loops.

Explore how firewalls establish security boundaries between networks with different trust levels, using ACLs to filter traffic by IP address, port, and protocol, and examine first-generation packet filtering firewalls.

Examine generation two proxy firewalls for network infrastructure, detailing circuit level and application layer proxies, their authentication, ACLs, and content filtering through deep packet inspection and caching.

Trace the evolution of firewalls from packet filtering to stateful and dynamic packet filtering. Learn how state tables govern inbound access and why kernel proxy firewalls are largely historical.

Explore firewall rules such as the default deny rule, ACLs, ingress and egress filters, and the importance of documenting rules and enabling remote logging for compliance.

Architect firewalls as security boundaries between trusted and untrusted network segments, using external and internal firewalls, a DMZ with NAT/PAT, and a VPN concentrator for encrypted access.

Explore dynamic IP address configuration with DHCP in enterprise networks, detailing client discovery, server offers, request, and acknowledgments, while guarding against rogue servers, address depletion, and using DHCP snooping.

Explore domain name system fundamentals, including name resolution, DNS zones, and internal versus external DNS, with TTL caching and service records for directory services.

Explore a DNS architecture with private and public namespaces, using domain controllers as DNS servers, a caching-only forwarder, and split-DNS in a DMZ to support public services.

Explore the DNS resolver client, including preferred and alternate DNS servers, resolver cache and TTL, and the DNSSEC role in authenticating responses against attacks such as poisoning.

Explore how X.500 directory services provide authentication and authorization for trusted principals, using Kerberos and Active Directory to govern domains, while PKI strengthens authentication with digital certificates for remote access.

Trace the evolution of network authentication from password-based methods to secure, certificate-enabled schemes, including PAP, CHAP with zero-knowledge proof, MS-CHAP v2, and EAP with LEAP and PEAP, SSL tunnels.

Examine x.500 directory services as a global authentication and authorization framework, using domain controllers, replication, organizational units, and sites to support a trusted, hierarchical naming system with ldap and dns.

Trace the evolution of directory services from banyan vines to Microsoft Active Directory, covering global distributed databases, LDAP access, domains and trusts, and group policy basics.

Learn how Kerberos uses a kdc, principals, and two-ticket authentication to enable single sign-on within a realm of trusted users and resources, and how radius and diameter support remote access.

Explore diameter, the next generation of AAA services, replacing radius and tacacs, and enabling roaming between cellular carriers while maintaining authentication, credentials, and high-speed 4G LTE sessions.

Explain how NAT and PAT extend IPv4 by sharing public IPs and hiding private networks, then illustrate port forwarding and one-to-one mappings for application servers.

Hardening a bastion host reduces attack surface by dedicating services, applying timely patches, enforcing least privilege, and using firewalls, antivirus, HIPS, external vulnerability scans, and TPM-based integrity verification.

Learn how enterprise endpoint systems—desktops, laptops, and mobile devices—are secured through remote administration and centralized policy. Explore hardening, least privilege, antivirus, regular updates, and configuration management to protect these devices.

Explore how mainframes served many users via thin clients, with all processing on the mainframe and IPL boot events potentially exploited by unauthorized programs during scheduled or unscheduled reboots.

Learn the essentials of wireless networking, from access points and nics to personal, local, and metropolitan scales, covering 802.11 standards, mimo, and the shift from wep to wpa/wpa2.

Learn how wireless cells form, compare ad hoc and infrastructure networks with access points, and trace the evolution from fhss and dss to mimo across 2.4 and 5 ghz.

WEP aimed to secure wireless like wired networks but failed due to a shared short password, open authentication, weak RC4 encryption, and MAC address filtering.

Discover how clients connect in infrastructure-mode wireless networks via access points, roam between APs with the same SSID, and advance from WEP to WPA2 (RSN) for stronger security.

Explore the evolution from WEP to WPA and WPA2, including TKIP and AES, pairwise and groupwise keys, and the role of 802.1X, EAP, and the Wi-Fi Alliance.

Explore enterprise wireless security with 802.11i, detailing 802.1X flow among the supplicant, authenticator, and radius server, using certificates to establish an SSL tunnel and enable WPA2 encryption and VPN options.

Explore common wireless attacks, including wardriving and war chalking, WEP cracking, eavesdropping, and man-in-the-middle with rogue access points, and learn how isolation firewalls protect the LAN.

Change the default SSID and set a strong administrator password, avoid provocative SSIDs, and deploy WPA2 with AES/CMAC, enterprise and mutual authentication, and isolate wireless segments with firewalls and VPNs.

Explains how MIMO uses multiple transmitters, receivers, and spatially diverse antennas with DSP and phased arrays to boost data rates across multipath 2.4 GHz in 802.11n/ac networks.

Learn how denial of service and distributed denial of service attacks threaten availability of IT resources, from SYN flood and teardrop to botnets of zombies orchestrated via IRC chat rooms.

Review information theft types, including sniffing and man-in-the-middle attacks, DNS and ARP poisoning, and dumpster diving. Learn defense strategies like shielding and white noise to protect data.

Explore advanced persistent threats and cell phone risks, including stealthy, targeted intrusions, reconnaissance, cover tracks, pivoting, and threats like cloning, tumbling, hotspots, sniffers, and data theft.

Provides a review of network technology and security topics, including the roadsign model, IP suite, media, infrastructures, wireless tech, attacks, firewalls, VPNs, and wireless security from WEP to WPA2.