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ip address

jacob deiter
Ranch Hand

Joined: Apr 02, 2008
Posts: 576
I have computer having Broad band connection on it.How the IP address will be assigned to my computer.



1) IP address of computer is never changed?

2)I use Win XP ,If I use get IP address using Command prompt I get a address ,what is this number ? who will assign this address?,is it possible to change this address if so how?

3) If I get IP address using command prompt differs from address retrieved using some online tool


4) is it possible for a computer to a many ip address??
Henry Wong
author
Sheriff

Joined: Sep 28, 2004
Posts: 18552
    
  40

I have computer having Broad band connection on it.How the IP address will be assigned to my computer.


Depends on how it is configured. In most cases, the broadband modem gets the IP address from the service (DHCP). If you place a router between it and the computer, it can provide you IP address (same service (DHCP), but the address is likely NAT'ed for privacy). Or you can hardwire the address...


1) IP address of computer is never changed?


If it is hardwired. But if it comes from a service, it has an expiration date.


2)I use Win XP ,If I use get IP address using Command prompt I get a address ,what is this number ? who will assign this address?,is it possible to change this address if so how?


Same question and answer as above.

3) If I get IP address using command prompt differs from address retrieved using some online tool


Not sure of what you are asking.

4) is it possible for a computer to a many ip address??


Each interface can have an IP address. Furthermore, you can assign a virtual IP address too, so you can have a computer respond to many IP addresses on the same interface.

Henry


Books: Java Threads, 3rd Edition, Jini in a Nutshell, and Java Gems (contributor)
jacob deiter
Ranch Hand

Joined: Apr 02, 2008
Posts: 576
3) If I get IP address using command prompt differs from address retrieved using some online tool



I use Command Prompt the use ipconfig it gives a number ,but it i click URL "http://whatismyipaddress.com/" then it gives different number?
Henry Wong
author
Sheriff

Joined: Sep 28, 2004
Posts: 18552
    
  40

jacob deiter wrote:
3) If I get IP address using command prompt differs from address retrieved using some online tool



I use Command Prompt the use ipconfig it gives a number ,but it i click URL "http://whatismyipaddress.com/" then it gives different number?


This is because you are behind a NAT'ed device, such as a router. The IP address that is returned from ipconfig is correct, but it is private to the network you are in -- from outside of the private network, all anyone sees is the IP address of the router (which is what is returned from the external site).

Henry
jacob deiter
Ranch Hand

Joined: Apr 02, 2008
Posts: 576
so If a computer(A) is behind a router then How the computer(A) is accessed from outside of router.Which ip address should be used by outsiders to access the computer(A)
Henry Wong
author
Sheriff

Joined: Sep 28, 2004
Posts: 18552
    
  40

jacob deiter wrote:so If a computer(A) is behind a router then How the computer(A) is accessed from outside of router.Which ip address should be used by outsiders to access the computer(A)


Well, simply... It can't be acessed. That's why the network is private. The machines in the network can access the outside -- and all be seen as if it came from the router, but there is no easy way for the outside to get to any of the machines in the network.

Now, the router can forward a port. For example, you can configure the router to forward port 8080 on the router to another port on a machine in the private network. This will allow you to access services on the private network, by accessing ports on the router. But it has to be configured. You can't access an arbitrary port on an arbitrary machine in the network.

Henry

kritika das
Greenhorn

Joined: Jun 17, 2011
Posts: 10
It is possible to change the IP address by manipulating proxy settings.
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: ip address
 
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