Re-install Windows = New IP?

[Distinct]

Hello,

I recently re-installed Windows XP and wiped the hard drive on an old computer. Would that assign this computer with a new IP address?

 

[Guest]

Maybe. What is your computer connected to? IP addresses are usually tracked by MAC addresses.

Grumpy

 

[Distinct]

I'm connected to a Net Gear router, and then DSL modem.

 

[Zenthar]

Depends on how the router assigns IP addresses. As Grumpy9117 said, the IPs are tracked by MAC Addresses so just wiping the drive will not change anything. However, IP assignments also have a "lease time" which mean that after a while, the IP might change after a simple reboot.

Most of the time the IP of your machine shouldn't be a concern to you. Maybe if you tell us WHY it would be a concern for you, we can give proper advices.

 

[Distinct]

I'm an IT student and was curious, I asked a couple of my friends and they were not sure, so what better place to ask then here?

 

[Zenthar]

OK, IT student so you can get the detailed answer . IP addresses are assigned by something called a DHCP server, in most houses, it's the router. When a PC starts, it broadcasts a DHCP request (because it doesn't have a network configured, it cannot do otherwise), the DHCP server catches it and sends a reply; this reply contains, among other things, the IP address. The DHCP linked the given IP to the MAC address of the requester and this IP address comes with a "lease time", when it expires the DHCP might reassign this IP to another PC. If the same PC does a 2nd DHCP request within the lease time, it might be reassigned the same address. Some router support features such as assigning a STATIC IP to a specific MAC address (necessary when you want to run a server behind a router). I think a device can also send an explicit "release" of the IP to the DHCP so it can reuse the IP before the lease expires.

In windows, to get a new IP address, you can probably just open a command prompt (DOS screen) and type:

ipconfig /renew

There is a lot to learn about networking if you are interested, it is incredibly complex without being overly complicated. You just need to understand the way protocols encapsulate one another.

 

[sub mesa]

So what if you are connected to a router you have an INTERNAL IP anyway, the external IP is known by the router, and is what identifies you on the internet. Your internal IP is only relevant to your router and your local network; not on the internet.

 

[Zenthar]

Was that a question of affirmation?

Anyhow, yes, the IP address assigned by the router is INTERNAL and cannot be reached from the internet. The only reachable IP address is the one assigned by your ISP. How can someone connect to you from the Internet then? He cannot without using some other mechanism. For that, most routers use Port Forwarding which mean that any data received on a TCP/UDP port is automatically sent to a fixed internal IP address.

If you want to know more about that, see NAT.

 

[Distinct]

Thanks for the explanation Zenthar! Interesting stuff! Thanks for the links to, I'm looking at this like a preview for my future classes

 

[Zenthar]

If you need other readings, here are a couple more:
■IP
■Ethernet
■DNS
■TCP/UDP
■TLS (often known as SSL)