Every network interface card or network adapter has its unique MAC address. Usually a MAC address is written as a 12 digit hexadecimal number. In windows computer if you want to view your MAC address then go to cmd and type ipconfig/all
then
Monday, September 6, 2010
What are MAC addresses?
MAC address or Media access control.
Every network interface card or network adapter has its unique MAC address. Usually a MAC address is written as a 12 digit hexadecimal number. In windows computer if you want to view your MAC address then go to cmd and type ipconfig/all
Every network interface card or network adapter has its unique MAC address. Usually a MAC address is written as a 12 digit hexadecimal number. In windows computer if you want to view your MAC address then go to cmd and type ipconfig/all
What is Internal IP address and external IP address?
Now days most people use a router proxy or NAT box ( for more information about NAT click here) or some other device to connect to the internet. Have you ever wondered how to find out your own internal IP address. Finding your Internal IP address is not difficult task. Just follow the steps:
1:click on start.
2:click on run
3:type cmd
4:and then type ipconfig.
Step 1: picture click on it for larger view.
Step 2: picture click on it for larger view
step3: picture click on it for larger view
step 4: picture click on it for larger view
To find out your public IP address that others with whom you are communicating. To do this just open your browser and type www.cmyip.com
Click on it for larger view.
step 4: picture click on it for larger view
To find out your public IP address that others with whom you are communicating. To do this just open your browser and type www.cmyip.com
What is NAT?
NAT or Network Address Translation
.For example let us assume that there are 100 employees in an office. Every employee has a phone extension number. There is a receptionist in the office that controls all incoming and outgoing phone calls in the office. Let us call her NAT. Receptionist has a list of employees names and their respective extension numbers. Now let see how incoming and outgoing calls are handled.
Out going calls: Employee calls the receptionist and then calls the destination number. The person at the destination number will only see the main office line phone number and not the employees inside desk number. This give the employees security and prevents annoying people from calling them. It also allows the office to use one single main office phone number to large number of employees. Hence, reducing the total number of telephone numbers are needed.
A NAT system operates in the same way. All the employees in the office are given a unique internal IP addresses which normally cannot be accessed from outside the network. When a system wants to connect to the internet, then the router assigns the system a public IP addresses that has been bought by the company. The internal IP address of the employees remains protected.
When the internet was initially created, there was no real shortage of IP addresses. However as internet usage increases an acute shoratge of IP addresses was seen world wide. This lead to the emergence of NAT.
Advantages of NAT.
1: Reduces need for IP addresses
2: Improve security basis implementation of networks.
Out going calls: Employee calls the receptionist and then calls the destination number. The person at the destination number will only see the main office line phone number and not the employees inside desk number. This give the employees security and prevents annoying people from calling them. It also allows the office to use one single main office phone number to large number of employees. Hence, reducing the total number of telephone numbers are needed.
A NAT system operates in the same way. All the employees in the office are given a unique internal IP addresses which normally cannot be accessed from outside the network. When a system wants to connect to the internet, then the router assigns the system a public IP addresses that has been bought by the company. The internal IP address of the employees remains protected.
Classes of IP addresses
There are five classes of IP addresses :
Class A: ranges from 1.0.0.0 to 127.0.0.1
Class B: ranges from 128.0.0.1 to 191.255.255.255
Class C: ranges from 192.0.0.0 to 223.255.255.255
Class D: ranges from 224.0.0.0 to 239.255.255.255
Class E: ranges from 240.0.0.0 to 255.255.255.255
There are five classes of IP addresses. In class A first 8 bits represent network ID and last 24 bits represent host ID. Then in class B the 16 bits represent network ID and the last 16 bits represent the host ID. Class C first 24 bits represent the network ID and last 8 bits represent host ID. In Class D all the 32 bits represent the multicast group ID.
What is IP address
Every computer connected to internet has its unique IP address associated with itself. An IP address acts as an unique identity of a computer at which it can be contacted. If the attacker wants to attack your system he first nedd to know your IP address. All the data send or recive by a particular system is by IP addresses.
It is important for someone to protect his or her IP address while working on the internet because the IP address is like youe mobile numberin the real world.The first job of the attacker is to find out your IP address.
An IP address is a 32 bit long address which is divided into four sub parts.
example: 172.16.254.1
Each 8 bit contain numbers from 1 to 255.
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