Lesson 4. The Intricacies of TCP/IP Protocols and Wireless Network Protection

TCP/IP

The foundational communication protocol for the internet, TCP/IP governs how data is packaged, addressed, transmitted, routed, and received.

Transmission Control Protocol (TCP)

A connection-oriented protocol that ensures data is delivered reliably between systems using a method called the three-way handshake.

Internet Protocol (IP)

Responsible for addressing and routing data across networks, IP defines how packets are formatted and delivered from source to destination.

IPv4

A 32-bit addressing system displayed in decimal format (e.g., 192.168.0.1) and divided into four octets.

IPv6

A 128-bit IP addressing system that uses hexadecimal numbers and is separated by colons.

Static IP Address

An IP address manually assigned to a device that does not change over time.

Dynamic IP Address

An automatically assigned IP address that can change periodically, typically managed by a DHCP server.

DHCP

A network protocol that automatically assigns IP addresses to devices.

APIPA

A fallback system that assigns an address in the 169.254.x.x range if a DHCP server is unavailable.

FTP

Uses ports 20/21 to transfer files between systems.

SSH

Uses port 22 and provides a secure command-line interface to manage devices over a network.

Telnet

Uses port 23 and provides a command-line interface like SSH, but without encryption.

SMTP (Simple Mail Transfer Protocol)

Uses port 25 to transfer email between servers. It is a protocol used for outgoing mail.

DNS (Domain Name System)

Uses port 53 to translate domain names (like www.google.com) into IP addresses. It is essential for navigating the internet.

HTTP (Hypertext Transfer Protocol)

Uses port 80 and is the protocol used by web browsers to load webpages. It is not secure by default.

POP (Post Office Protocol v3)

Uses port 110 to retrieve emails from a server. It downloads and often deletes messages from the server after access.

NetBIOS

Uses ports 137/138/139 and enables communication between Windows systems on a local network. It works with TCP/IP via NBT.

IMAP (Internet Message Access Protocol)

Uses port 143 and allows users to access and manage email directly on the mail server. Emails stay on the server unless deleted.

SNMP (Simple Network Management Protocol)

Uses ports 161/162 and allows network administrators to monitor and manage devices remotely.

BGP (Border Gateway Protocol)

Uses port 179 and is the protocol used by internet service providers to exchange routing information on the internet.

LDAP (Lightweight Directory Access Protocol)

Uses port 389 and is used to access and manage directory information such as user data and permissions.

HTTPS (HTTP Secure)

Uses port 443 to secure HTTP communication using SSL or TLS. It ensures encrypted data transmission between browsers and servers.

LDAPS (LDAP Secure)

Uses port 636 to provide secure access to LDAP services via SSL/TLS encryption.

FTPS (FTP Secure)

Uses ports 989/990 and encrypts FTP data transfers using SSL/TLS for secure file transfers.

Wireless Network

A network that connects devices without physical cables, typically using Wi-Fi. While convenient, it requires strong security to prevent unauthorized access.

Wireless Access Point (WAP)

A device that transmits and receives wireless signals, allowing Wi-Fi-enabled devices to connect to a wired network. Placement is key to ensure optimal signal distribution.

Wireless Site Survey

An analysis conducted to evaluate wireless signal strength, interference, and optimal placement of WAPs. It helps determine network feasibility and identify problem areas like dead zones or interference sources.

Co-Channel Interference

Occurs when multiple wireless networks use the same frequency channel, leading to signal overlap. Using non-overlapping channels (like 1, 6, 11 on 2.4 GHz) helps avoid this.

Channel Interference

Caused by other devices or obstacles (including people) that interfere with wireless signals. Site surveys help detect and mitigate such interference.