IP Address

 What is IP Address ?

1. An IP address is a unique identifier for a node or host in a TCP/IP based network.
2. The IP address is designed and control by Internet Assigned Number Authority (IANA).
3. It manage the space of IP address and delegates of Regional Internet Registries_(RIR).
4. RIR allocates IP blocks to ISPs_(Internet Service Providers).

ISP:- An internet service provider (ISP) is a company that provides the Internet Services. ISPs can provide this access through multiple means, including dial-up, DSL, cable, wireless and fiber-optic connections.Example; Airtel,Jio,Vodaphone etc.

Types of Address:-

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There are two types of Address available:

1) Physical Address

2) Logical Address

Physical Address:-

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1. Physical Address known as Ethernet Address or MAC address.
2. Full form of MAC is Media Access Control.
3. MAC address has 48 bit or 12 digit.
4. This digit always write in hexadecimal_(00:0a:45:2e:52:28) format.
5. In Microsoft O/S you can use getmac command to sho MAC address.
6. In Linux O/S you can use ifconfig command to sho MAC address.

Logical Address:-

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There are two types of logical Address available:

1) IPv4

2) IPv6

Before understand the IPv4 & IPv6 everyone must know the Number System.

What is number system ?

A numeral system is a writing system for expressing numbers; that is, a mathematical notation for representing numbers of a given set, using digits or other symbols in a consistent manner. The same sequence of symbols may represent different numbers in different numeral systems.

Different conversion available on it:-

1) Binary to other conversion

    Binary - Decimal

    Binary - Octal

    Binary - Hexadecimal

2) Decimal to other conversion

    Decimal - Binary

    Decimal - Octal

    Decimal - Hexadecimal

3) Octal to other conversion

    Octal - Binary

    Octal - Decimal

    Octal - Hexadecimal

4) Hexadecimal to other conversion.

    Hexadecimal - Binary

    Hexadecimal - Decimal

    Hexadecimal - Octal

Sr.	Number System	Base	Number
1	Binary	2	0,1
2	Octal	8	0,1,2,3,4,5,6,7
3	Decimal	10	0,1,2,3,4,5,6,7,8,9
4	Hexadecimal	16	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15

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Convert the Decimal number into Binary number.

Example:-    (25)10 = (---)2

1st Method:-

Formula:-

128    64    32    16    8    4    2    1    =    255

16    8    4    2    1    =    31_(Formula)

1     1    0    0    1    =    25      

Answers is (25)10 = (11001)2  

2nd Method:-

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Convert the Binary number into Decimal number.

Example:-    (11001)2 = (---)10

16    8    4    2    1    =    31_(Formula)

1     1    0    0    1    =    (16+8+1 = 25)

Answer is "25".

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Convert Hexadecimal number to Decimal number.

Example:-    (2A5)16 = (---)10

Convert Decimal number to Hexadecimal number.

Example:-    (677)10 = (---)16

Hint:- "Use BCD Code"

(8 4 2 1) (8 4 2 1) (8 4 2 1) = BCD Code

(0 1 1 0) (0 1 1 1) (0 1 1 1)

Answer is "011001110111"

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# Classes of IPv4 & Range:-

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Class	Range
A	0-127
B	128-191
C	192-223
D	224-239
E	240-255

Class	Range	Default Mask
A	1-126	255.0.0.0
B	128-191	255.255.0.0
C	192-223	255.255.255.0
D	224-239	Multicasting
E	240-255.255.255.254	Experimental

# Private IP Address:-

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Class	Start Range	End Range
A	10.0.0.0	10.255.255.255
B	172.16.0.0	172.31.255.255
C	192.168.0.0	192.168.255.255

# Loopback IP Address:-

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This type of ip address is used for check the lan card status & maintain the background network connectivity. You can check the lan card is working or not with any ip address of this range via ping command.

Example:- ping 127.0.10.0.1

If you reply 4 msg thereafter you lan card is in working condition.

Start Range - 127.0.0.0    or    127.0.0.1

End Range - 127.255.255.255    or    127.255.255.254

# APIPA IP Address:-

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This is the IP address that is assign by the Operating System Self. If DHCP server did not provide the ip address & subnet mask to computer machine_(DHCP Client).

Start Range - 169.254.0.0    or    169.254.0.1

End Range - 169.254.0.0    or    169.254.255.254

# What is DHCP ?:-

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1. DHCP is a protocol that is used for assign the automatic IP address to DHCP client.
2. If any condition if DHCP server nor reachable to DHCP client to assign the ip address that time operating system Automatic create a IP address with subnet mask that is known as APIPA IP Address.
3. DHCP work on Application Layer of OSI model.
4. Port number of DHCP Server is 67 & DHCP Client is 68.

# What is NAT/PAT ?:-

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1. NAT stand for Network Address Translator & PAT stand for Port Address Translator.
2. This is the protocol that is used for convert the private ip address to public IP address or public ip address to private ip address.
3. NAT convert one Private IP to One Public IP Address.
4. PAT convert the Multiple Private IP Address to one Public IP Address.

# What is DNS ?:-

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1. DNS is a name resolution technic that is used for convert the ip address to name_(www.google.com) or name_(www.google.com) to ip address.
2. DNS work as a phone book of your cell phone. You can remember every contact number but we can remember the name of contact person same as we can not store the every web site ip address but the name of web site we can save in our mind. So DNS work as a database that store the website with name or ip address.
3. The port number of DNS is 53.

# Difference Between Private & Public IP Address:-

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Key	Private IP Address	Public IP Address
Scope	Private IP address scope is local to present network.	Public IP address scope is global.
Communication	Private IP Address is used to communicate within the network.	Public IP Address is used to communicate outside the network.
Format	Private IP Addresses differ in a uniform manner.	Public IP Addresses differ in varying range.
Provider	Local Network Operator creates private IP addresses using network operating system.	Internet Service Provider (ISP) controls the public IP address.
Cost	Private IP Addresses are free of cost.	Public IP Address comes with a cost.
Locate	Private IP Address can be located using ipconfig command.	Public IP Address needs to be searched on search engine like google.
Range	Private IP Address range:10.0.0.0 – 10.255.255.255, 172.16.0.0 – 172.31.255.255, 192.168.0.0 – 192.168.255.255	Except private IP Addresses, rest IP addresses are public.
Example	Private IP Address is like 192.168.11.50.	Public IP Address is like 17.5.7.8.