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It happens at some part of the boot process. It's independent of when you login. It's just that sometimes it takes a little longer than others.

I just want to know WHEN my ADSL router will assign my machine an IP address? Is it as soon as Win 7 gets to the login screen or is it done at power on? It's not a static IP address; it just assigns the next available one that's not in use. Thanks a lot!

In this excerpt from Answercast #67, I look at the timing involved when a computer assigns an IP address.

When is an IP address assigned

It varies. It's actually, typically part of the boot sequence - but exactly where is kind of difficult to say.

Your machine definitely has an IP address before you login to it because you could login to it remotely. So by definition, if you can log into it remotely with something like Remote Desktop, it has an IP address - and that had to happen before you logged in at the console.

The best I can say really is that somewhere between the time you begin the boot and the login screen appears, somewhere in there it should get an IP address.

"It depends"

Now, here's the problem (and here's why I even have to be squishy on that); if you login quickly, it's possible that you may not have an IP address yet. We often see this with wireless networks, which for whatever reason can take some more time to connect than other networks and therefore can take more time to make that request for an IP address.

So in reality, what's going on here is the process to request an IP address, to request the assignment of an IP address, or the process to enable and turn on the network adapter and do all that, begins sometime while you're booting. It takes however long it takes (usually it's pretty quick; sometimes it can be a little bit long), but it runs in parallel then to whatever else is happening on the screen.

So, the login screen may come up, you may have an IP address at that point; you probably will have an IP address pretty soon thereafter. If you login quickly,... well, it's possible that you may login to a machine that hasn't really reached that "I've got an IP address" point yet.

But that's really all it is. It's happening at some part of the boot process. It's independent of when you login. It's just that sometimes it takes a little longer than others.

Article C5994 - November 5, 2012 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

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