DHCP and 3 Way-handshake

DHCP: Dynamic Host Configuration Protocol

·         It will assign IP address dynamically to the clients

·         It will works on DORA process

·         Port numbers are 67 – for client, 68 – for server

·         DORA – Discover Offer Request Acknowledgment

Default Gateway and APIPA

Default Gateway:

All the PC’s connected with in the Network is communicated with other network devices by using this Default-Gateway only

Internet Access for specific IP Range

              

Scenario: We have to configure firewall such that only computer with specific IP can access the internet.

IP addressing

Comparision between IP address and MAC address

IP (Internet Protocol)/  logical address	MAC (Media access control) address/  Physical address
It is a 32 bit address                        [8.8.8.8]	It is a 48 bit address            [8:8:8:8:8:8]
It is represented in doted decimal representation	It is represented in hexadecimal representation
It is used to uniquely identify a device within different network	It is used to uniquely identify a device within the same network
	Note: first 24 bits represents manufacturer           Last 24 bits represents device

List of Protocols and there Port numbers

Protocol	Port number	Protocol Used
FTP File Transfer Protocol	20 - for data 21 - for connection establishing	TCP/UDP TCP
SFTP Secure File Transfer Protocol	22	TCP
SSH Secure Shell Protocol	22	TCP
Telnet	23	TCP
SMTP Simple Mail Transfer Protocol	25	TCP

TCP/IP Utilities

TCP/IP Utilities

it is used to troubleshoot and to maintain a Network without any Problems

• PING (Packet Internet Gopher)

  Ping is used to find the connected device is alive are not. Ping uses a special protocol called ICMP (Internet Control Message Protocol)

  We can check it for Connected devices, websites, DNS, DHCP and Print server etc

• Tracert

It is similar to Ping, it identifies the path through which the packets is going to reach the Destination.

OSI Model:

OSI Model:

Open System Interconnection is a reference model to describe how data communication takes place between one computer to other computer in a network.

it was proposed by International Organization for Standardization (ISO)

•  OSI is evolved from experiences with ARPANET

Format                       Layer                                             Brief Function

--------------------------------------------------------------------------------------------------------------------------

Data                 -- Application Layer               -- DHCP, FTP, HTTP

Data                 -- Presentation Layer            -- File type ex: JPEG, TXT; Compression

Data                 -- Session Layer                   -- Security, connection establishment,                                                                                           connection release, type of communication

Segment            -- Transport Layer              -- Error control, messages to segments,                                                                                       TCP/UDP

Packet              -- Network Layer                 -- Logical Address & Translation logical to                                                                                    Physical address

Frame              -- Data link Layer                 -- Raw data to logical structure called Frame, A  

Cable types

 Types of connecting cables:

1. Straight cable

2. Cross cable

3. Roll over cable

Note:

• For similar devices we will use Cross Cables.
• For different Devices we will use Straight Cables.
• For configuration through console port we will use Roll over Cable.

Types & Ways of Communications

Types of communications :

1: Simplex communication:  It is a only one way communication.

 Ex: television, radio

Basics of Networking

What is Network:

It is a group of connected devices to share data, information and to communicate with each other.

What is Networking:

            The process of configuring networking devices to make a network for communication is called networking.

Networking devices are 

• Hub
• Bridge
• Switch and
• Router...etc