Introduction to Network

CCNA : Introduction index

Network introduction

Private & Public IP

ISP: Internet service provider.
User  <------>   Router   <--------> ISP   <-------------->  INTERNET <------> Web
IANA: Internet Assigned Number Authortiy
NAT: Network address translation.

Class A:
10.0.0.0  to  10.255.255.255  (private ip)

Class B:
172.16.0.0  to  172.31.255.255 (private ip)

Class B:
192.168.0.0  to  192.168.255.255 (private ip)


NAT Introduction:
Network Address translation: is a method of converting private ip to public ip.

Uses: To handle shortage of IPv4 address.
          Hide networking addressing shcemes.


Three types:
Static NAT
Dynamic NAT
Port Address Translation PAT


Static NAT: (1 to 1)
One to One mapping with private ip to public ip
Entire configuration will done by manually.
Inside interface to router where lan configuration,  out-side interface to router where public ip configuration.

Command:
ip nat inside source static 192.168.1.1  50.1.1.1



Dynamic NAT:
1 to 1
One to One mapping with private ip to public ip
Entire configuration will done by device.


Port Address Transformation PAT: (1000 --> 1 Public IP)
For differentiation we will use different port number along with public ip:
Default http port number 80
Default FTP port number 21

Save the number of IP addresses (60,000 local users -----> 1 public ip )


PAT (Dynamic NAT overload )
Port Address Translation:
Pool Name:
Converting multiple IP addresses into single public ip address.