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DHCP Broadcast flag handling in Windows 7

DHCP Broadcast flag handling in Windows 7

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1.     DHCP Broadcast flag:

DHCP messages have ‘flags’ field. The first bit in this field indicates whether the client is expecting a broadcast or unicast response from the DHCP server \ Relay agent. When the bit is set to 1, it indicates that the client expects broadcast response, and when the bit is set to 0, it indicates that the client expects a unicast response. While the majority of the DHCP Servers and Relay Agents support both the values for the broadcast flag, there are still few of them which support only either of the values of the broadcast flag.

2.     Behaviour change in Windows 7:

           In Vista, the default broadcast flag value is set to ‘1’. But it had caused inter-operability issues with some 3rd party router based DHCP Servers \ Relay agents  that did not support broadcast flag ‘1’. Therefore in Windows 7, the behaviour change introduced would try with both the values for the broadcast flag (toggling between ‘0’ & ‘1’) and also would cache the last successful broadcast bit setting for which the client received IP address. This is to ensure that the client acquires the address properly, irrespective of the support for the flag from DHCP Server \ Relay Agent. That is, during address acquisition, first the client will try with the broadcast flag set to 0 and it sends 4 DHCP DISCOVER messages at exponential intervals for a total duration of one minute. If the client does not get any response (i.e. DHCP OFFER), then broadcast flag is toggled to 1 and again 4 DISCOVER messages are sent at exponential intervals. At least one of the flag setting is expected to succeed when the DHCP server \ Relay Agent is reachable. The successful broadcast flag is cached, and that cached flag is used as the starting broadcast flag, during the next time of address acquisition.

Another difference is, in Vista, toggling can happen (if configured) only for the address acquisition. But in Windows 7, toggling is extended to INIT-REBOOT scenario as well. In this scenario, after getting valid address, if the client gets a disconnect - connect, then the client will first send 3 DHCP REQUESTs with the broadcast flag (with which it had acquired the address). If there is no response from the server, the client will then send 3 DHCP REQUEST with the alternate Broadcast flag. If again, there is no response, then the gateway reachability check is done. If the gateway is reachable, the old IP configuration is kept. If the gateway is also not reachable, then the old configuration is removed.

So, the default behaviour is to have starting broadcast flag as 0 and toggling is ON. This can be changed by changing the configuration settings in registry as given below.  

3.     Configuring broadcast flag settings:

 

      The default broadcast bit behaviour of Windows 7 is expected to work fine in most of the scenarios, and therefore it is least expected from the users to modify any broadcast bit related settings, unless the user clearly understands the impact. Also note that the explained registry based procedure to configure broadcast bit settings may not be maintained in future versions of windows, unless it is required. There are two kinds of broadcast flag settings that can be configured.

 

i)                    The starting broadcast flag, with which the first set of DHCP DISCOVERs start. By default it starts with ‘0’.

ii)                  The toggle setting, which will indicate whether the broadcast flag can be toggled (if the starting broadcast flag fails). By default, toggling is ON.

  

3.1 Configuring the starting broadcast flag:

The starting broadcast flag value can be specified at two levels.

i)                    For a specific interface.

ii)                  Globally based on the interface type. This option needs to be chosen, only if the value of the MediaType and PhysicalMediumType of the interface are known.

 

3.1.1  Configuring the starting broadcast flag for a specific interface :

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

ii)                 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.

iii)               Right-click DhcpConnForceBroadcastFlag, and then click Modify.

iv)                In the Value data box, type the broadcast flag (0 or 1), and then click OK.

v)                  Close Registry Editor.

vi)                Restart the machine.

 

3.1.2  Configuring the starting broadcast flag globally for an interface type:

i.                    Click Start, type regedit in the Start Search box, and then click regedit in the Programs list. Collapse this imageExpand this image If you are prompted for an administrator password for confirmation, type your password, and click Continue.

ii.                  Locate and then click the following registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dhcp\Parameters

iii.                On the Edit menu, point to New, and then click Key.

iv.                 Type DhcpGlobalForceBroadcastFlag for the name of the registry subkey, and then press ENTER.

v.                   Click DhcpGlobalForceBroadcastFlag, point to New on the Edit menu, and then click Key.

vi.                 Type the Value of MediaType(Real Value, not this string) for the name of the registry subkey, and then press ENTER. Following are some of the possible values.

 

Value of MediaType

Media

0

Unknown adapters like remote access adapters

1

Wireless

14

Ethernet

vii.                 Click Value of MediaType, point to New on the Edit menu, and then click DWORD Value to create a new registry entry.

viii.               Type Value of PhysicalMediumType (Real Value, not this string) for the name of the registry entry, and then press ENTER.

ix.                   Right-click on this registry entry, and then click Modify.

x.                     In the Value data box, type the broadcastflag(0 or 1), and then click OK.

xi.                   Review the final output. The final output should resemble the following:

[HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ Dhcp \ Parameters \ DhcpGlobalForceBroadcastFlag \ Value Of MediaType] "Value of PhysicalMediumType"= dword : [1 or 0]

xii.                 Close Registry Editor.

xiii.               Restart the machine.

3.2 Configuring the toggle settings:

 This setting is used to indicate whether the client can perform toggling of broadcast flag. This setting can be defined only at the interface level. By default toggling is ON.

i.                      Click Start, type Regedit in the Start Search box, and then click regedit in the Programs list. If you are prompted for an administrator password 

             for confirmation, type your password and click Continue.

ii.                    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.

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

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

v.                    Right-click DhcpConnEnableBcastFlagToggle, and then click Modify.

vi.                  In the Value data box, type 1 or 0 (ON\OFF), and then click OK.

vii.                Close Registry Editor.

viii.              Restart the machine.

4.     Verification of broadcast flag settings:

 

i)                    Install the latest network monitor from http://www.microsoft.com/downloads/ .

ii)                  Apply filter ‘DHCP’ and start capturing the packets.

iii)                In an elevated command prompt, do ipconfig /releaseName of Interface”, specify the interface name in which you want to verify.

iv)                 Then, do ipconfig /renew  Name of Interface

v)                  You can find that DHCP packets are getting captured on network monitor. Expand the flags field of DHCP DISCOVER packet, the first bit of this 

            field  denotes the broadcast flag set.

vi)                By default, you should be seeing 8 DISCOVER packets for a total duration of 2 mins. The first 4 DISCOVER packets will have the flag set to ‘0’ and the 

            next 4 will have the flag set to ‘1’.

 

5.     FAQ on broadcast flag settings:

 

i)                   I have configured the broadcast flag settings, but still the setting does not come up in DHCP messages?

            Follow the steps exactly as specified in section 3. After modifying the registry settings, immediately restart without doing any other IP  related operations. As specified in verification section (4), use netmon to verify the broadcast flag set in the DHCP message. Ensure that you are verifying the broadcast flag on the DHCP messages that originate only from your machine.

 

ii)                  I have a domain joined IPsec enabled machine and the machine does not get IP address in certain routers?

This will happen when the router does not support broadcast flag ‘1’. When DHCP DISCOVERs are sent with broadcast flag 0, the corresponding OFFERs are dropped by IPsec as they are unsolicited unicast messages. To resolve this issue, the IPsec administrators are recommended to have UDP traffic exemption from port 67 to 68 (for DHCP messages). The issue could also be solved by updating the router firmware. But since, the external routers cannot be controlled always, IPsec admins are advised to have this exemption.

 

iii)                The machine takes around a minute to get the IP configuration, when I move between networks?

This can happen if the broadcast flag supported at your source network and destination network are different. Please update your router firmware for the issue to be fixed.

 

iv)                Does the above method to configure broadcast flag settings apply to Vista as well ?

Yes. Though the default behaviour of Vista is different, the configuration and verification methods specified here, can be applied to Vista as well. In Vista, by default, the starting broadcast flag is 1 and toggling is OFF.

 

v)                  My WWAN card does not get IP address on a domain joined IPsec enabled machine ?

This is known issue in Windows 7 Beta, which is fixed in further releases of Windows 7 versions. Temporarily this be could be solved, by changing the interface-specific ‘starting broadcast flag’ to ‘1’ [See configuration section 3.1.1] 

 

6.     Troubleshooting Broadcast flag issues:

If you think, that your machine is not getting an address, because of broadcast flag issue, then here are steps to troubleshoot.

i)                    Start capturing DHCP packets on the interface, as specified in the verification section (4).

ii)                  If the default settings are not modified, you should be seeing 4 DISCOVERs sent on the first minute with a specific broadcast flag (0 by default), and during the second minute another 4 DISCOVERs will be sent with the alternate broadcast flag.

iii)                If 8 DISCOVERs are not sent as mentioned above, then verify whether the toggle setting [specified in configuration section 3.2] is correct.

iv)                If 8 DISCOVERs are properly sent and none of them got any response from the DHCP server, then it is likely that DHCP server is not reachable, and the issue is not associated with broadcast flag.

v)                  If a specific set of DISCOVERs got OFFER as the response, but still the client did not accept the OFFER, and continues sending the DISCOVER, then it is likely that you are having a router which does not support broadcast flag 1 and a domain joined IPsec enabled machine. Refer to FAQ section for the resolution.

 

 

 

 

 

Comments
  • 214 Microsoft Team blogs searched, 92 blogs have new articles in the past 7 days. 218 new articles found

  • I am having connectivity problem in windows 7 rc 64 bit. Have to boot to xp to get the dsl modem to connect to internet then only it works in windows 7 rc is it due to dhcp problem? How can I know that my connectivity problem is due to DHCP?

  • hi,

    In order to figure out if your issue is due to DHCP or not, please try the folowing:

    Try assigning static IP address on Win7RC and then see if the issue is still there. Please provide us the exact repro steps.In order to figure out the issue, please provide us DHCP traces at dhcpblog at microsoft dot com.

    1) Copy-paste the following exact instructions in a dhcptrace.cmd file

    @echo off

    IF "%1" == "-start" (

    netsh dhcpclient trace disable > NUL

    netsh trace stop > NUL

    echo.

    echo Starting dhcp trace..

    echo.

    del /Q %TEMP%\DhcpTraces

    echo.

    echo Creating the folder %TEMP%\DhcpTraces

    echo.

    mkdir %TEMP%\DhcpTraces

    ipconfig /all > %TEMP%\DhcpTraces\IpConfigStart.txt

    REG QUERY "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /v BuildLabEx > %TEMP%\DhcpTraces\BuildLabVersion.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /s > %TEMP%\DhcpTraces\TcpIpParametersStart.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters" /s > %TEMP%\DhcpTraces\TcpIp6ParametersStart.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Dhcp\Parameters" /s > %TEMP%\DhcpTraces\DhcpParametersStart.txt

    netsh trace start scenario=AddressAcquisition ^

    provider=Microsoft-Windows-TCPIP ^

    provider=Microsoft-Windows-winsock-AFD ^

    provider=Microsoft-Windows-WFP ^

    tracefile=%TEMP%\DhcpTraces\addracq-cap.etl protocol=UDP overwrite=yes report=no capture=yes >> %TEMP%\DhcpTraces\OtherLogs.txt

    netsh dhcpclient trace enable >> %TEMP%\DhcpTraces\OtherLogs.txt

    netsh dhcpclient trace dump

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpv4trace.log %TEMP%\DhcpTraces\dhcpv4tracestart.log >> %TEMP%\DhcpTraces\OtherLogs.txt

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpv6trace.log %TEMP%\DhcpTraces\dhcpv6tracestart.log >> %TEMP%\DhcpTraces\OtherLogs.txt

    echo Dhcp tracing successfully started

    goto eof

    )

    IF "%1" == "-stop" (

    echo.

    echo Stopping dhcp trace. Please wait for a few seconds..

    ipconfig /all > %TEMP%\DhcpTraces\IpConfigStop.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /s > %TEMP%\DhcpTraces\TcpIpParametersStop.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters" /s > %TEMP%\DhcpTraces\TcpIp6ParametersStop.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Dhcp\Parameters" /s > %TEMP%\DhcpTraces\DhcpParametersStop.txt

    netsh dhcpclient trace disable >> %TEMP%\DhcpTraces\OtherLogs.txt

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpcsvc.etl %TEMP%\DhcpTraces\dhcpcsvc.etl >> %TEMP%\DhcpTraces\OtherLogs.txt

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpcsvc6.etl %TEMP%\DhcpTraces\dhcpcsvc6.etl >> %TEMP%\DhcpTraces\OtherLogs.txt

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpqec.etl %TEMP%\DhcpTraces\dhcpqec.etl >> %TEMP%\DhcpTraces\OtherLogs.txt

    netsh dhcpclient trace dump

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpv4trace.log %TEMP%\DhcpTraces\dhcpv4traceend.log >> %TEMP%\DhcpTraces\OtherLogs.txt

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpv6trace.log %TEMP%\DhcpTraces\dhcpv6traceend.log >> %TEMP%\DhcpTraces\OtherLogs.txt

    netsh trace stop >> %TEMP%\DhcpTraces\OtherLogs.txt

    move /y %TEMP%\DhcpTraces\addracq-cap.etl %TEMP%\DhcpTraces\addracq-cap-uncorrelated.etl >> %TEMP%\DhcpTraces\OtherLogs.txt

    netsh trace correlate %TEMP%\DhcpTraces\addracq-cap-uncorrelated.etl %TEMP%\DhcpTraces\addracq-cap.etl retainpii=yes >> %TEMP%\DhcpTraces\OtherLogs.txt

    echo.

    echo Dhcp tracing successfully stopped.

    echo.

    echo Trace Location: %TEMP%\DhcpTraces

    echo.

    echo Please send this folder to the feature team.

    goto eof

    )

    echo -start : starts the dhcp trace

    echo -stop : stops the dhcp trace

    echo  eg: : dhcptrace -start

    echo  : dhcptrace -stop

    :eof

    2) Now on a machine where you are able to repro this issue, in an elevated prompt,  please run "dhcptrace.cmd -start"

    3) Repro the issue. You should not have seen the connectivity as you said.

    4) After repro is over, wait for 2 mins and then run "dhcptrace.cmd -stop"

    5) The log files are copied in %TEMP%\dhcptraces.

    6) Please compress and send us this folder.

    It will be really helpful if you can provide us the above mentioned logs to figure out the exact issue.

    Thanks

  • I'm using the windows 7 32bit os.  After about a week of using it I started having a problem getting on the internet.  If my computer sits too long or even if i just turn it on, I have no internet or network access.  I have to type in the IP address and trouble shoot to apply a fix everytime I want to use the internet. When I do that I get a message that said  DHCP is not enabled.  How do I fix this problem so I don't have to go through so much to use my internet?

  • hi Martina,

    On troubleshooting you get " dhcp is not enabled" as you applied static IP address on the adapter. Without typing in the IP address, please try to troubleshoot before even typing the IP address. Also, can you please provide me the DHCP traces as mentioned above in one of the comments. Please start the tracing, let your computer be idle for long period, then resume it and see if you get the connectivity. As you said you should not have get the connectivity. Wait for 3-4 mins. Then stop the tracing. Also, when you don't get connectivity, try doing "ipconfig /release and ipconfig /renew" and see if you get the connectivity. Also try connect/discoonect on adapter and disable/enable and let us know if you are able to get connectivity with any of these.

    Thanks

    teamdhcp

  • A test machine windows 7 x64 has problems with dhcp.

    We did a trace and found that the discover is done and 2 offers are received from the client but the client does not react with a request message.

    We use a 3rd party dhcp server over cisco ip helper. But to be sure we used our old microsoft 2003 dhcp server and we saw that the client gets the offer also from the microsoft server but nothing. The client just issues a few more discovers.

    What could be the issue? ipsec domain - we don't have this enabled. Firewall has been put off.

    Kind regards,

    Patrick

  • hi Patrick,

    This looks to be some issue where the offer is not reaching DHCP client or being dropped by DHCP client because of some reason and then DHCP client sending the Discovers again and again.

    In order for us to investigate the issue, please provide us the DHCP traces, steps being mentioned in one of the above comments on this blog by teamdhcp.

    Please let me know in case you face any issue or have any doubt.

    Thanks

    Ranu

  • hi dhcpteam.

    Excuse my bad english, i'm from germany, but the problems are the same here over the ocean!

    Here at home I have a dhcpd running on a openSUSE 11.0 LINUX box, could it be that this is a buzzword for your dhcp-client?

    All I can see is a never ending story of DHCPDISCOVER and DHCPOFFER messages in my logfile, but no address for the Win 7 notebook ... very poor!

    All other Windows PC were working fine here in my network, especially ALL XPs are working great!

    And now this very poor result called Windows 7 ... is this the result the users wanted as it could be seen in the ads on the TV???

    I tried ALL og your hints concerning the registry setting ... nothing happend ...

    WIN7 is useless even as VISTA when it would not work in a standard network environment, so I have to step back to XP!

    And I had an alp dream last night:

    I'm the manager of over 500 PCs in a spread school network, using 9 (NINE!!) UNIX Servers ... ALL running dhcpd with mac-2-ip fixed adresses ... and when we upgraded to WIN 7, NO PC will ever work for month ...

    So what should I tell to my boss?

    My only idea at this time is:

    Don't switch to WIN 7, wait for SP2 or 3 or 4, until they have implemented the same dhcp client again that they previously used in XP.

    Or are there any better ideas from your side??

    (NO! We will NOT use Windows servers, to expensive, too much work to handle, much to instable as seen in one of our neighbourhood schools, where we have a never ending story of re-installations and service pack night-sessions etc...)

    Thank's a lot for reading my comment,

    Michael.

  • hi Michael,

    In order to figure out if your issue is due to DHCP or not, please try the folowing:

    Please provide us the exact repro steps.In order to figure out the issue, please provide us DHCP traces at dhcpblog at microsoft dot com.

    1) Copy-paste the following exact instructions in a dhcptrace.cmd file

    @echo off

    IF "%1" == "-start" (

    netsh dhcpclient trace disable > NUL

    netsh trace stop > NUL

    echo.

    echo Starting dhcp trace..

    echo.

    del /Q %TEMP%\DhcpTraces

    echo.

    echo Creating the folder %TEMP%\DhcpTraces

    echo.

    mkdir %TEMP%\DhcpTraces

    ipconfig /all > %TEMP%\DhcpTraces\IpConfigStart.txt

    REG QUERY "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /v BuildLabEx > %TEMP%\DhcpTraces\BuildLabVersion.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /s > %TEMP%\DhcpTraces\TcpIpParametersStart.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters" /s > %TEMP%\DhcpTraces\TcpIp6ParametersStart.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Dhcp\Parameters" /s > %TEMP%\DhcpTraces\DhcpParametersStart.txt

    netsh trace start scenario=AddressAcquisition ^

    provider=Microsoft-Windows-TCPIP ^

    provider=Microsoft-Windows-winsock-AFD ^

    provider=Microsoft-Windows-WFP ^

    tracefile=%TEMP%\DhcpTraces\addracq-cap.etl protocol=UDP overwrite=yes report=no capture=yes >> %TEMP%\DhcpTraces\OtherLogs.txt

    netsh dhcpclient trace enable >> %TEMP%\DhcpTraces\OtherLogs.txt

    netsh dhcpclient trace dump

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpv4trace.log %TEMP%\DhcpTraces\dhcpv4tracestart.log >> %TEMP%\DhcpTraces\OtherLogs.txt

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpv6trace.log %TEMP%\DhcpTraces\dhcpv6tracestart.log >> %TEMP%\DhcpTraces\OtherLogs.txt

    echo Dhcp tracing successfully started

    goto eof

    )

    IF "%1" == "-stop" (

    echo.

    echo Stopping dhcp trace. Please wait for a few seconds..

    ipconfig /all > %TEMP%\DhcpTraces\IpConfigStop.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /s > %TEMP%\DhcpTraces\TcpIpParametersStop.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters" /s > %TEMP%\DhcpTraces\TcpIp6ParametersStop.txt

    REG QUERY "HKLM\SYSTEM\CurrentControlSet\Services\Dhcp\Parameters" /s > %TEMP%\DhcpTraces\DhcpParametersStop.txt

    netsh dhcpclient trace disable >> %TEMP%\DhcpTraces\OtherLogs.txt

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpcsvc.etl %TEMP%\DhcpTraces\dhcpcsvc.etl >> %TEMP%\DhcpTraces\OtherLogs.txt

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpcsvc6.etl %TEMP%\DhcpTraces\dhcpcsvc6.etl >> %TEMP%\DhcpTraces\OtherLogs.txt

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpqec.etl %TEMP%\DhcpTraces\dhcpqec.etl >> %TEMP%\DhcpTraces\OtherLogs.txt

    netsh dhcpclient trace dump

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpv4trace.log %TEMP%\DhcpTraces\dhcpv4traceend.log >> %TEMP%\DhcpTraces\OtherLogs.txt

    copy /y %SYSTEMDRIVE%\Windows\System32\Logfiles\WMI\dhcpv6trace.log %TEMP%\DhcpTraces\dhcpv6traceend.log >> %TEMP%\DhcpTraces\OtherLogs.txt

    netsh trace stop >> %TEMP%\DhcpTraces\OtherLogs.txt

    move /y %TEMP%\DhcpTraces\addracq-cap.etl %TEMP%\DhcpTraces\addracq-cap-uncorrelated.etl >> %TEMP%\DhcpTraces\OtherLogs.txt

    netsh trace correlate %TEMP%\DhcpTraces\addracq-cap-uncorrelated.etl %TEMP%\DhcpTraces\addracq-cap.etl retainpii=yes >> %TEMP%\DhcpTraces\OtherLogs.txt

    echo.

    echo Dhcp tracing successfully stopped.

    echo.

    echo Trace Location: %TEMP%\DhcpTraces

    echo.

    echo Please send this folder to the feature team.

    goto eof

    )

    echo -start : starts the dhcp trace

    echo -stop : stops the dhcp trace

    echo  eg: : dhcptrace -start

    echo  : dhcptrace -stop

    :eof

    2) Now on a machine where you are able to repro this issue, in an elevated prompt,  please run "dhcptrace.cmd -start"

    3) Repro the issue. You should not have seen the connectivity as you said.

    4) After repro is over, wait for 2 mins and then run "dhcptrace.cmd -stop"

    5) The log files are copied in %TEMP%\dhcptraces.

    6) Please compress and send us this folder.

    It will be really helpful if you can provide us the above mentioned logs to figure out the exact issue.

    Thanks

    Ranu

  • Hi dhcpteam ...

    unfortunally you haven't provided any e-mail address where I could send the compressed content of the DhcpTraces folder to....

    BTW:

    After all these night sessions with Win7 and all the frustrating results trying to setup the LINUX dhcpd-server and all the the other routers I decided to step back to XP ... and wait until Win8 or Win9 or Win10 is released hoping that one of these releases will work stable and without any problems, even as Win XP does.

    Not only for my home PCs in my lab, but also for the networks in all schools I'm administrating.

    Sorry,

    Michael.

    PS: But I'd like to send you the dhcp-trace results if I would get an email addy from your side :.(

  • hi Michael,

    In the earlier reply I mentioned the email id. You might have missed it.Please send the traces at  dhcpblog at microsoft dot com.

    Thanks

    Ranu

  • Hello I have the same issue with windows 7 32-bit not picking up IP from a 2K3 DHCP server, these are Intel DG45FC ITX with core 2 duo E8500, the Windows 7 64-bit works on the fly but some how with 32-bit does not. Please help. I got that dhcptrace directory will send it to you via email

    Thanks

    Bill

  • Hi, I'm having the same problem, dhcp assignment not working, static IP is OK. This is a win7 x64 enterprise, the same h/w was formerly running Vista without problems. There has been made a clean install on the box. I have posted dhcp trace generated with the script above..

    dhcpserver is a server 2008.

    Kind Regards

    Bent Lauritsen

  • On the DCHP server, in the Address Leases, I get Bad address showing up in the Name field on the address leases when I configure the windows 7 computer to get it IP address from the DCHP server. The Bad address slams over the name of the XP computers that have the address leased. This causes an IP conflict statement to the user of the XP computer.

    We have a Windows 2003 server that is handling our DHCP server.  When we connect our first Window 7 computer to the network, our DHCP server start getting Bad Address on the TCP/Ip List.  When we disconnet the Win 7 computer, the Bad Address stops.

    DHCP Server: server 2003 R2 Standard Edition SP 2

    DHCP: Version 5.2.3790.3959

    Windows 7: PRO  

    All Are 32 bit

  • hi Dennis,

    Do you mean that if you try to join a new XP machine instead of Win7, then things are OK and server assigns address properly but if a new Win7 machine is joined to the network, it will always lead to getting an address marked as "Bad Address"?

    Do some machines have static IP address in the network due to which the address is marked as "Bad Address"?

    Please explain the scenario and the issue in details.

    If possible, please also provide netmon capture to us when the Windows 7 machine tries to connect to the server and causes the issue.

    Thanks

    teamdhcp

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