Notes: What is Networking | Pre Security | THM

What is Networking

Networks - things(devices) connected

Internet:

- one giant network

- made up of many small networks all joined together = private networks

- networks connecting small networks = public networks

ARPANET (1960s) United States Defence Department - first documented network in action

1989 Tim Berners-Lee invented World Wide Web (WWW)

Devices can be identified by:

- IP Address (Internet Protocol)

- Media Access Control (MAC) Address

Example of an IP Address: 192.168.1.1

192: Octet # 1, 0-255

168: Octet # 2, 0-255

1: Octet # 3, 0-255

1: Octet # 4, 0-255

IP addressing and subnetting

IP addresses can change from device to device, but only one can be active at a time within the same network

IP addresses follow a set of standard known as protocols

Devices can be on both private and public networks

What type of IP address (public or private IP address) the device have, depend on where it is

Public IP address - used to ID device on internet

Private IP address - used to ID device among other devices

Example:

Two devices have different private IP addresses, but the same public IP address if any data are sent to internet

Public IP addresses are given by your Internet Service Provide (ISP) at a monthly fee

Different IP address versions:

- IPv4: 2^32 IP addresses = 4.29 billion

- IPv6: 2^128 IP addresses = 340 trillion-plus (help solve the shortage of IPv4 addresses)

Media Access Control (MAC) Address:

- all devices have a physical network interface - a microchip board found on device's motherboard <- assigned a unique MAC address

- 12 character hexadecimal number (base 16 number system) split into two's and separated by a colon

Example: a4:c3:f0:85:ac:2d

first six: a4:c3:f0 = represent the company/vendor that made the network interface

last six: 85:ac:2d = is a unique number

a4:c3:f0 = Intel

Spoofing: MAC addresses can be faked/spoofed

Ping uses ICMP (Internet Control Message Protocol) packets to check connection/performance between devices

Time travelled between devices is measured by ping using ICMP's echo packet and ICMP's echo reply

Ping, tool, comes preinstalled on OS like Windows and Linux

Syntax: ping 'IP address' or ping 'website URL'

Example: ping 192.168.1.254

Results will show number of packets sent and received, percentage of packet loss and time