This document discusses IP addresses, DNS, DHCP, and related networking concepts. It defines an IP address as a unique number assigned to devices on a network that allows them to be identified and located. It describes IPv4 and IPv6 address standards and how network and host IDs are defined for different address classes. It also explains loopback addresses, APIPA addresses, DNS and how it translates names to addresses, and DHCP and how it dynamically assigns IP addresses and configuration information to devices on a network.

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IP ADDRESS
DNS
DHCP

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IP Address
• What is an IP address ?
 Internet protocol address
 unique identifying number given to every single
computer on the Internet.
 IP address is a special serial number used for
identification.
 allows the machine to be located by other machines on
the network

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IP Address
• IP addresses can be either static or dynamic
 Static IP – Fixed and never changes
 Dynamic IP – temporary and could change
at any time

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IP Address
• Two Standards of IP address –
IPv4 – 32 bit binary bits
 4 numbers separated by dots.
 Example - 25.161.13.191
IPv6 – 128 bit binary bits
 eight groups of hexadecimal numbers separated by
colons(:).
 Example - 2001:0db8:85a3:0000:0000:8a2e:0370:7334

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IP Address
• IP address is divided in 2 parts :-
Network ID and Host ID
 Network ID – It’s a ID of the network and resembles the
network.
 Host ID – It’s a identification of host on the network.
Net ID Host ID
Example – 25.161.13.191

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IP Address Classes

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IP Address
• IP Address classes –
Class Class Range Address Range Supports
Class A 0-126 10.0.0.0 to
10.255.255.255
16 million hosts on
each of 127 networks.
Class B 128-191 172.16.0.0 to
172.31.255.255
65,000 hosts on each
of 16,000 networks.
Class C 192-223 192.168.0.0 to
192.168.255.255
254 hosts on each of 2
million networks.
Class D 224-239 NA Reserved for
Multicasting
Class E 240-255 NA Experimental; used for
research

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IP Address
• How to define network id and host id in IP
address classes ?
10.12.34.10 :- 11001100.11100111.11111000.11001100
 Class A –
First octet shows the network id and rest 3 octets shows the
host id.
Net Host
ID ID
2^24 16,777,216 hosts per network
10.12.34.10

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IP Address
• How to define network id and host id in IP
address classes ?
10.12.34.10 :- 11001100.11100111.11111000.11001100
 Class B –
First 2 octets show the network id while the last 2 denotes
the host id.
Net Host
ID ID 2^16 16,384 hosts per network
10.12.34.10

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IP Address
• How to define network id and host id in IP
address classes ?
10.12.34.10 :- 11001100.11100111.11111000.11001100
 Class C –
First 3 octets show the network id while the last 1 denotes the
host id.
Net Host
ID ID
2^8 256 hosts per network
10.12.34.10

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LOOPBACK Address

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IP Address
• Loopback address – (127.0.0.1)
 Also called as Localhost.
 Loopback has no hardware associated with it.
 Allows us to test ip software without worrying about the
broken or corrupted driver or hardware.
 Loopback interface never goes down.
 Used for management on routers.

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APIPA Address

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IP Address
• APIPA address – Link-local address
 Automatic Private IP Address.
 Range - 169.254.0.1 to 169.254.255.254
 With APIPA, client machines can automatically self-configure
an IP address.
 Meant for small business environments, usually less than 25
clients.
ex. Home , small intranet LAN’s.
 How to check if your computer is enabled for APIPA?

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DNS

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DNS
• DNS – Domain Name System
 DNS is a protocol.
 Used to translate a user friendly domain name into an IP address.
 DNS implements a distributed database to store the name and
address information for all public hosts on the Internet.
 DNS resolver – contacts DNS server to determine servers IP
address.
 Best example of DNS is Internet.

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DNS
• How DNS works :- www.google.com
3. That’s in my cache.
It maps to IP address 70.42.251.42
5
DNS 4. great! I will cache
server 3 that for a while.
2
5.Thanks for
the direction DNS Server
4
1
1. I need direction to 2. The domain name is
www.google.com www.google.com is not
in my database

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DHCP

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DHCP
• DHCP :-
 Dynamic host configuration protocol.
 Configures devices that are connected to a network so that they can
communicate using the IP address.
 Maintains database of available IP addresses and configuration
information.
 Allocate IP address to a client on a lease.
Lease :- amount of time that a given IP address will be valid for a
computer.
 Lease duration is set to 8 days by default.
 DHCP Pool – contains list of available IP address.

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DHCP
• How DHCP works :-
 DHCP works on DORA process.
1) Discover
2) Offer
3) Request
4) Acknowledge

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THE END