Invalid IP Address 169.254.x.x

Hi. I'm a DSL tech support agent and we have a lot of problems with customers getting invalid ip address especially after installing a replacement modem.  I take them through a list of things to do but it rarely seems to work.  My most recent adventure down this rabbit hole was with a customer who had a brand new modem and a brand new computer with Vista on it.  Here's what I tried:

- ipconfig /all got us a 169.254.x.x ip address and no default gateway
- ipconfig /release gave us the same number
- ipconfig /renew failed
- ftp gave no message at all
- netsh winsock reset appeared successful (restart)
- netsh int ip reset resetlog.txt appeared succussful(restart)
- NIC appeared OK and said it was working properly
- uninstalled NIC and let Vista reinstall it on a restart but it did not help
- pulled power cord out of modem for 10 secs
- shut computer down, pulled power cord out of modem, pulled phone cord from modem, inserted phone cord then power cord and restarted computer after lights were solid
- tried "diagnose and repair" but it failed
- ensured firewall was off
- tried running a winsock fix utility
- tried reinstalling IPv4 on local area connection
- tried creating a new broadband PPPoE connection
- tried booting in safe mode with networking
- tried manually assigning the ip addresses

I'm tired of spending up to 3 hours on a call trying to fix this only to refer them to our fee-based tech support people.  It seems there is or should be a simple solution to get the computer and modem to talk to each other so we can surf into the modem.  I know my customers don't like being on the phone that long.  What am I missing?  What will actually work?  Is there a simple solution? 


Question Info

Last updated January 21, 2020 Views 158,765 Applies to:

Hi Sparkchaser, 

Welcome to Windows Vista Answers Forums!

When a DHCP client boots up, it first looks for a DHCP server in order to obtain an IP address and subnet mask. If the client is unable to find the information, it uses APIPA (Automatic Private IP Addressing) a feature in Windows Vista to automatically configure itself with an IP address and subnet mask when a DHCP server isn't available. The IP address range is through, a range that has been reserved especially for Microsoft.

If a Windows Vista computer fails to get an IP address from DHCP Server, then you may have to confirm if the DHCP Server supports the BROADCAST flag.

To resolve this issue, disable the DHCP BROADCAST flag in Windows Vista. To do this, follow these steps:

1)    Click Start, type regedit in the Start Search box, and then click reedit in the Programs list. If you are prompted for an administrator password or for confirmation, type your password, or click Continue.

2)    Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\ {GUID}

In this registry path, click the (GUID) subkey that corresponds to the network adapter that is connected to the network.

3)    On the Edit menu, point to New, and then click DWORD (32-bit) Value.

4)    In the New Value #1 box, type DhcpConnEnableBcastFlagToggle, and then press ENTER.

5)    Right-click DhcpConnEnableBcastFlagToggle, and then click Modify.

6)    In the Value data box, type 1, and then click OK.

7)    Close Registry Editor.

For more information you may refer the following link:

Windows Vista cannot obtain an IP address from certain routers or from certain non-Microsoft DHCP servers.

Important: The above mentioned method tells you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs.

How to back up and restore the registry in Windows:

Hope this information is helpful.

Praseetha K

Microsoft Answers Support Engineer
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