Sesión 2

Introduction to IP Addressing and Networking

Overview of the Session

• The session aims to cover the fundamentals of IP addressing, key networking devices, and communication protocols used in real-world environments. This is an introductory level discussion for those who may need a refresher on networking topics.

• By the end of the session, participants should be able to identify how an IP address is structured, calculate basic networks, recognize common networking devices (both current and obsolete), and understand essential services that support internet functionality.

Technical Definitions and Concepts

• The speaker will introduce specific technical definitions related to networking concepts as needed throughout the session. Participants are encouraged to ask specific questions in a designated forum rather than for attendance purposes.

• A QR code will be provided for accessing YouTube sessions related to this topic, including previous and upcoming discussions. Communication through YouTube is emphasized for clarity during the learning process.

Understanding IP Addresses

What is an IP Address?

• An IP address serves as a unique identifier for each device connected to a network, allowing other devices to locate it for information exchange. It is added to the header of various Protocol Data Units (PDUs) such as messages or packets depending on which layer of TCP/IP is being utilized at that moment.

• There are two types of identifiers: physical (like MAC addresses) and logical (like IP addresses). The latter can be modified by network administrators unlike physical addresses which are fixed at manufacture time.

IPv4 vs IPv6

• Despite the existence of IPv6 since 2013, approximately 80% of global communications still rely on IPv4 due to legacy systems still in use today. IPv4 remains relevant because many computers continue operating under this protocol despite advancements in technology.

• An IPv4 address consists of four octets separated by periods (e.g., 192.168.1.100), with each octet representing 8 bits ranging from 0 to 255—allowing up to approximately 4 billion unique addresses compared with vastly more available under IPv6 using hexadecimal notation across eight groups instead of four octets.

Classes of IPv4 Addresses

Identifying Address Classes

• The first octet determines the class type: Class A ranges from 0–126; Class B from 128–191; Class C from 192–223; while classes D and E are reserved for special uses like multicast or experimental purposes respectively but not assigned directly within networks.

• Each class has different capacities: Class C supports up to 256 usable addresses per network segment while Classes A and B accommodate larger numbers based on their respective ranges—Class B allows between 256 -65,536 addresses while Class A supports over 16 million addresses per network segment depending on configuration needs within private networks versus public ones used globally online.

Public vs Private Addresses

Understanding Public and Private Addresses

• Public IP addresses are globally unique identifiers assigned by Internet Service Providers (ISPs) that allow direct access over the internet whereas private IP addresses function solely within local networks without visibility outside them—these include ranges like 10.x.x.x or 192.x.x.x among others designed specifically for internal use only without conflict against public allocations made elsewhere online through NAT processes when connecting externally via routers configured accordingly .

Network Address Translation (NAT)

• NAT enables routers to replace private internal device addresses with public-facing ones when communicating externally so that responses return correctly back through established connections initiated internally—this ensures seamless interaction between local devices needing internet access while maintaining security protocols inherent within localized setups preventing unauthorized external access attempts .

Subnetting Basics

Importance of Subnetting

• Subnetting divides larger networks into smaller manageable segments enhancing performance control over traffic flow reducing broadcast domains thereby improving overall efficiency especially useful in organizational settings where multiple departments require distinct operational capabilities yet share common infrastructure resources effectively .

Calculating Subnets

• Key formulas such as 2^n help determine potential subnet configurations based upon binary positioning indicating how many subnets can exist given certain parameters set forth during initial design phases ensuring optimal resource allocation tailored towards specific departmental needs without compromising integrity across shared platforms utilized collectively .

Subnetting and Addressing in Networking

Understanding Subnets

• Each subnet is divided into ranges: 0-63, 64-127, 128-191, and 192-255. This indicates that each subnet will have a diagonal addressing of /26.

• The exercise involves creating four large subnets for an educational institution using BLCM (Binary Length Class Mask).

Address Requirements

• Total address requirements include 481 for students, 69 for instructors, 23 for administrators, and 2 for WAN communication, totaling to 575 addresses needed.

Calculating Addresses

• To determine the number of addresses required within the supernet converted into subnets, we sum all necessary addresses.

• Using the formula 2^n, we find that 2^10 provides enough addresses (1024), which satisfies our need of 575.

Class B Addressing

• A Class B non-routable address is identified as 172.16.0.0/22; this means that out of the total of 32 bits in addressing, we reserve bits for routing.

Student Network Calculation

• For student networks needing at least 481 usable addresses: 512 = (2^9), thus satisfying the requirement after subtracting network and broadcast addresses.

Instructor and Administrator Networks

Instructor Network Setup

• For instructors requiring at least 69 usable addresses: 128 = (2^7), resulting in a usable count of 126. This meets their needs effectively.

Administrator Network Setup

• Administrators require at least 23 usable addresses; hence 32 - n = (32 -5), leading to a subnet mask of /27 with a total of 30.

WAN Addressing

WAN Configuration

• For WAN connections needing only two IP addresses: using 2^n -2, results in a subnet mask of /30 providing sufficient unique identifiers.

Introduction to DHCP

What is DHCP?

• Dynamic Host Configuration Protocol automatically assigns IP configurations including IP address, subnet mask, DNS values when devices connect to networks.

DHCP Process Explained

• When connecting to a network, DHCP attempts to assign an IP address dynamically until successful connection occurs.

Understanding DNS

Role of DNS in Networking

• Domain Name System translates user-friendly URLs into machine-readable IP addresses facilitating easier navigation on the internet.

How DNS Works

• When accessing a URL like google.com, if not found locally cached it queries external DNS servers until resolved back into an accessible format.

Networking Devices Overview

Hub vs Switch Comparison

• Hubs function like multi-outlet connectors without control tables causing potential collisions; they are now considered obsolete compared to switches.

Switch Functionality

Switches operate with control tables allowing targeted data transmission between specific ports reducing collision risks significantly.

Router Functions

Router Capabilities

• Routers work primarily at layer three managing both physical and logical addressing while connecting different network technologies efficiently.

Understanding Firewalls and Network Security

Types of Firewalls

• There are three main types of firewalls:

• Packet filtering firewalls, which examine individual packets based on source and destination IP addresses.

• Stateful firewalls, which track active connections to determine if incoming traffic is part of an established session.

• Application firewalls, which analyze traffic based on specific applications, allowing or blocking certain functionalities (e.g., video calls on WhatsApp).

Access Points and Wireless Networks

• Access points facilitate wireless connections within a network by providing a Service Set Identifier (SSID), allowing devices to connect wirelessly.

• These devices centralize connections and serve as the first line of defense against unauthorized access through password protection.

Evolution of Wireless Technology

• Wireless standards have evolved since 1999 from 802.11b to current standards like AX, improving speed, range, and reducing latency issues.

• Current transmission frequencies include 2.4 GHz, 5 GHz, and now also 6 GHz for higher speeds up to 9.6 Gbps under optimal conditions.

Wi-Fi Security Protocols

• WPA2 was succeeded by WPA3 for enhanced security; however, sharing passwords indiscriminately undermines this security.

• Strong passwords should be over 12 characters long with a mix of symbols, letters, and numbers; changing default SSIDs is also recommended.

Fundamental Network Services

Common Network Ports

• Essential network services utilize specific ports:

• HTTP (port 80), HTTPS (port 443), SMTP (ports 25 & 587), DNS (port 53), FTP (ports 21 &22), SSH (port 22), DHCP (ports 67 &68).

Importance of RFC Standards

• The Internet Engineering Task Force maintains protocols through RFC documents that standardize how internet technologies function.

Best Practices in Networking

Encryption vs. Encoding

• It’s crucial to use encrypted protocols like HTTPS instead of HTTP for secure communications; the correct term is "cifrado" rather than "encriptado."

Addressing IP Concerns

• Understanding valid IP addresses includes recognizing public versus private addresses and utilizing NAT for address translation effectively.

Q&A Session Insights

Loopback Functionality

• A loopback address allows testing network interfaces by pinging the local host at IP address 127.0.0.1.

NAT Explained

• NAT serves as a method for multiplexing multiple private addresses into one public address while maintaining unique identifiers for each device.

DNS Functionality Issues

• If a DNS server fails but you know the site's IP address, you can still access it directly without resolving its domain name.

Enhancements in Wi-Fi Security

Improvements in WPA3 Over WPA2

• WPA3 introduces SAE protocol offering better resistance against dictionary attacks by preventing common password vulnerabilities often exploited in brute-force attempts.