NETWORKING

Computer Network

A collection of computers and resources connected to facilitate communication

Network Interface

Hardware that connects a computer to a network such as Ethernet or WiFi card

Network Services

Software services required for networking such as firewall and authentication

Hub

A device that broadcasts data to all devices in the network

Switch

A device that sends data to a specific device using MAC address

Router

A device that routes data between different networks using IP address

Gateway

A device that connects different types of networks together

TCP/IP

A set of protocols used for communication over networks

Network Interface Layer

Handles sending and receiving data on the physical network

Internet Layer

Responsible for addressing

Internet Protocol (IP)

Handles IP addressing and routing of packets

Address Resolution Protocol (ARP)

Resolves IP address to hardware address

Internet Control Message Protocol (ICMP)

Provides error messages and diagnostics

Internet Group Management Protocol (IGMP)

Manages multicast group memberships

Transport Layer

Provides communication services between applications

Transmission Control Protocol (TCP)

Reliable protocol with error checking and packet recovery

User Datagram Protocol (UDP)

Fast but unreliable protocol without connection setup

Application Layer

Allows applications to communicate over the network

Hypertext Transfer Protocol (HTTP)

Used for transferring web pages

File Transfer Protocol (FTP)

Used for transferring files between systems

Simple Mail Transfer Protocol (SMTP)

Used for sending emails

Telnet

Used for remote login to another computer

Domain Name System (DNS)

Converts domain names into IP addresses

Routing Information Protocol (RIP)

Used by routers to exchange routing information

Simple Network Management Protocol (SNMP)

Used for monitoring and managing network devices

ping

A command that sends ICMP echo request to test connectivity

traceroute/tracepath

A command that shows the path packets take to a destination

ip

A command used to display and configure network interfaces and routing

netstat

A command that shows network connections and statistics

ftp (command)

A program used to transfer files over a network

wget

A command used to download files from the internet

ssh

A command used for secure remote login to another system

ICMP ECHO_REQUEST

A packet sent by ping to check connectivity