Change IP

A

Assaf

Up to a few weeks ago, I was able to change my IP address with these commands:
ipconfig /flushdns
ipconfig /release
ipconfig /renew
But all of a sudden, I cant.
I talked to my ISP and they say that nothing change on their side and I
still have a dynamic IP.
I believe that maybe one of the updates is responsible for this, I update to
SP1 and almost every update exist for vista.
So, my question is, do you know maybe on an update that can cause this?
10x in advance.
 
W

William Anderson

Hey there Assal,

First off, can you do an ipconfig /all and post the Lease Obtained and Lease
Expires results in here?

Also, acquiring an address is part of the DHCP protocol in the TCP/IP Stack.
Now, you can check to see if you have your connection set to a static IP in
the connection config by doing the following:

Go to Start>Control Panel
Click on Network and Sharing Center
In the Connection section, click on View Status
Click on the Properties button (If you have UAC enabled, it will prompt you
for Admin Credentials)
Click and highlight Internet Protocol Version 4
Click the Properties button.
Make sure the "Obtain an IP Address Automatically" and "Obtain DNS Server
Address Automatically" options are selected. If not, select them, the click
OK, OK, and Close.

If they are set to automatic, then your machine is set for DHCP. Here's the
gist on how that works...remember DORA: Discover, Offer, Request, Acknowledge

Your PC goes out to the network and says "'I'm Here! Somebody give me an
Address!!!" (Discover)

Then the modem or router for your network (usually it's relayed from your
cable modem if you're direct connected) OFFERS your machine an address. If
your old address is still in the available pool, it will offer that one to
your machine.

Your machine then accepts the address, and sends a REQUEST notice saying
that it has an address.

When the machine makes that broadcast...the DHCP server (cable
modem/router/whatever) ACKNOWLEDGES the request and the machine is done.

Long story short, it's very feasible that your machine is still DHCP, and
there are no issues with the process, but your machine just happens to keep
being offered the same address.

So what you need to do is look at the lease info on the ipconfig /all. If
it's not more than a few days old, you're getting refreshed.

Does this help?

Best Regards,

Will
 
A

Assaf

First of all, 10x for the help, here is the lease info:

Lease Obtained. . . . . . . . . . : ‰…Â‡Ž‰™‰ 17 €â€Ëœâ€°ÂŒ 2008 20:28:15
Lease Expires . . . . . . . . . . : ‰…Â™Â‰ 21 €â€Ëœâ€°ÂŒ 2008 10:19:50

I dont know why it's written like this, the OS is in English.
I checked, DHCP is on.
Another thing, when I go to sleep, I turn off the computer, and in the
morning, when I connect, I get a new IP, although the modem stays connected
through out the night.
BTW, I dont use a router.
Again, 10x for the help.
 
W

William Anderson

Hey there Assaf,

With what you have there...it appears that you grabbed a new lease today
around 8PM in your TimeZone and the lease will be set to expire on the 21st
of this month. I would watch and see what it does after 10:20AM on the 21st
and see if the lease updates. Check the IP address then, and also check what
the obtained and expires dates are. Sound good?
 
A

Assaf

For sure, I'll do that.
10x.

William Anderson said:
Hey there Assaf,

With what you have there...it appears that you grabbed a new lease today
around 8PM in your TimeZone and the lease will be set to expire on the 21st
of this month. I would watch and see what it does after 10:20AM on the 21st
and see if the lease updates. Check the IP address then, and also check what
the obtained and expires dates are. Sound good?
 
S

Steve Winograd

Up to a few weeks ago, I was able to change my IP address with these commands:
ipconfig /flushdns
ipconfig /release
ipconfig /renew
But all of a sudden, I cant.
I talked to my ISP and they say that nothing change on their side and I
still have a dynamic IP.
I believe that maybe one of the updates is responsible for this, I update to
SP1 and almost every update exist for vista.
So, my question is, do you know maybe on an update that can cause this?
10x in advance.

As you know, the IP address is assigned by your ISP's DHCP server. The
DHCP server can assign you any address in its pool. It might be the
same address that you just released, and it might be a different
address.

The specification for DHCP doesn't require them to assign you a new
address.

I'm curious: why do you want a new address?
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional Program
http://mvp.support.microsoft.com
 

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