Mar 222008

After connecting your vista machine to your router it may not get the ip address from your DHCP server in this case this tutorial will help you to fix this issue.

Consider the following scenario

• You connect a Windows Vista-based computer to a network.

• A router or other device that is configured as a Dynamic Host Configuration Protocol (DHCP) server is configured on the network.

• The router or the other device does not support the DHCP BROADCAST flag.

In this scenario, Windows Vista cannot obtain an IP address.

Cause for the above problem

This issue occurs because of a difference in design between Windows Vista and Microsoft Windows XP Service Pack 2 (SP2). Specifically, in Windows XP SP2, the BROADCAST flag in DHCP discovery packets is set to 0 (disabled). In Windows Vista, the BROADCAST flag in DHCP discovery packets is not disabled. Therefore, some routers and some non-Microsoft DHCP servers cannot process the DHCP discovery packets.


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

Click Start–>Run type regedit click ok

If you are prompted for an administrator password or for confirmation, type your password, or click Continue.

Locate and then click the following registry subkey from left pane


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

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

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

Right-click DhcpConnEnableBcastFlagToggle, and then click Modify.

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

Close Registry Editor.

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  4 Responses to “Fix for Vista cannot obtain IP address from certain routers or DHCP Server”

  1. It tried this but it did not work.

  2. I believe I may have found the problem to some people not getting vista dhcp working with an xp server.

    The nic on the vista machine showed the packets going out, but no reply from the xp machine. DHCP rfc’s 1533, 1534, 1541 and 1542 show that the dhcp ports are 67 and 68. ( of 6 Aug 2008). Wireshark confirmed vista was using these ports. I then went to xp start/settings/control panel/network connections and looked at local area connection 2 (shared) properties. This is the internet connection sharing nic which has the dhcp server attached. I went to the advanced tab and in the internet connection sharing area clicked settings. Services comes up and showed dhcp (67) and dhcp (68) unchecked. DNS also unchecked.(we had to previously manually insert the dns server entries) I checked them all, a re boot and bingo!

    Since I made this change, my xp client pc also sends dhcp requests via ports 67 and 68 so I have no idea how the xp clients would have worked prior to the change.

    I hope this helps.

  3. My main computer (windows Xp) connected to the router would disconnect when i’d go online with 1 of my laptops(vista) for some reason.
    I managed to fix this problem by going to (main computer) xp start/ control panel/ network and internet connections/ network connections/ select local area connection 2, right click ,properties/advanced then untick internet connection sharing which allows other network users to connect through this computers internet connection.
    Hopefully this should fix the problem.

  4. Solved my problem!! Brilliant

    Using a Billion 7300G wifi/ADSL router with Vista.

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