HiWe are running an install of Server 2008 which we have had for roughly a month.On 2 occasions when we have rebooted the server, the subnet mask for all our set IP Addresses has been reset to 255.255.255.255Searching Google and this forum is turning up nothing for me andit's causing us a great deal of issues.CheersCraig.

hi carig,Please do not panic by seeing this subnet mask.the reason behind this is , you have enabled NAP on the DHCP scope . And this behavior only occurs if you have configured on DHCP on windows 2008. please right click on the scope and under NAP ( network access protection ) disable the option.best of lucksai

Hi SaiThanks for the response but NAP is already disabled on all scopes and we use static IP's anyway.It might be worth noting that this doesn't happen every time we reboot, just most of the time.CheersCraig

Hi craig,good day..Can you please confirm, if this behavior happening for only one subnet or any new subnet which you create ?also i would request you to provide netmon trace when clients perfrom ipconfig /release and ipconfig /renew to check the appropriate DORA process. sainath Windows Driver Development

Hi SainathWe use static IPs so DHCP shouldn't be an issue. The change is happening on the subnet for every IP address on the machine.CheersCraig.

Are you seeing the 255.255.255.255 in the TCP configuration UI or in the route table? (Route print from command prompt). All 255's is the proper mask for IP addresses in the route table, but of course not for the subnet as configured in the UI.

Hi craig,so i am confirming that we can eliminate DHCP as source of problem.so as a troubleshooting , i would like to check in the below locationhklm\system\ccs\services\tcpip.can you please extract hte below registry key and send it across to me ?and also if possible please start server in safe mode with networking and check the behavioralso please check if you provide 127.0.0.1 , is it still taking 255.255.255.255 ?if so there is possibility of a) network card problemb) winsock corruption.sainath Windows Driver Development

@TimHiThe subnets are shown in the UI, and obviously we can tell when we try to ping another machine.@SainathHi AgainYes we can eliminate DHCP. Unfortunately we can't start the server in safe mode as it is currently being used as our live webserver.Here is the requested key: WindowsRegistryEditorVersion5.00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip] "BootFlags"=dword:00000001 "DisplayName"="@%SystemRoot%\\system32\\tcpipcfg.dll,-50003" "Group"="PNP_TDI" "ImagePath"=hex(2):53,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,64,00,\ 72,00,69,00,76,00,65,00,72,00,73,00,5c,00,74,00,63,00,70,00,69,00,70,00,2e,\ 00,73,00,79,00,73,00,00,00 "ErrorControl"=dword:00000001 "Start"=dword:00000000 "Tag"=dword:00000003 "Type"=dword:00000001 "Description"="@%SystemRoot%\\system32\\tcpipcfg.dll,-50003" [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Linkage] "Bind"=hex(7):5c,00,44,00,65,00,76,00,69,00,63,00,65,00,5c,00,7b,00,43,00,37,\ 00,35,00,41,00,36,00,34,00,35,00,35,00,2d,00,34,00,34,00,46,00,33,00,2d,00,\ 34,00,44,00,38,00,37,00,2d,00,41,00,41,00,33,00,32,00,2d,00,36,00,30,00,42,\ 00,41,00,41,00,43,00,32,00,30,00,39,00,39,00,32,00,39,00,7d,00,00,00,5c,00,\ 44,00,65,00,76,00,69,00,63,00,65,00,5c,00,7b,00,33,00,37,00,37,00,42,00,43,\ 00,45,00,34,00,43,00,2d,00,36,00,36,00,30,00,31,00,2d,00,34,00,41,00,32,00,\ 34,00,2d,00,41,00,45,00,35,00,37,00,2d,00,30,00,46,00,42,00,42,00,41,00,34,\ 00,33,00,30,00,37,00,38,00,32,00,35,00,7d,00,00,00,5c,00,44,00,65,00,76,00,\ 69,00,63,00,65,00,5c,00,7b,00,39,00,46,00,34,00,35,00,44,00,41,00,44,00,36,\ 00,2d,00,30,00,30,00,39,00,35,00,2d,00,34,00,36,00,34,00,33,00,2d,00,42,00,\ 42,00,38,00,38,00,2d,00,33,00,41,00,33,00,31,00,33,00,39,00,31,00,43,00,45,\ 00,33,00,46,00,30,00,7d,00,00,00,5c,00,44,00,65,00,76,00,69,00,63,00,65,00,\ 5c,00,7b,00,46,00,44,00,37,00,39,00,46,00,44,00,37,00,41,00,2d,00,44,00,46,\ 00,32,00,46,00,2d,00,34,00,38,00,44,00,33,00,2d,00,42,00,32,00,31,00,34,00,\ 2d,00,35,00,34,00,36,00,37,00,32,00,42,00,39,00,38,00,36,00,43,00,43,00,42,\ 00,7d,00,00,00,00,00 "Route"=hex(7):22,00,7b,00,43,00,37,00,35,00,41,00,36,00,34,00,35,00,35,00,2d,\ 00,34,00,34,00,46,00,33,00,2d,00,34,00,44,00,38,00,37,00,2d,00,41,00,41,00,\ 33,00,32,00,2d,00,36,00,30,00,42,00,41,00,41,00,43,00,32,00,30,00,39,00,39,\ 00,32,00,39,00,7d,00,22,00,00,00,22,00,7b,00,33,00,37,00,37,00,42,00,43,00,\ 45,00,34,00,43,00,2d,00,36,00,36,00,30,00,31,00,2d,00,34,00,41,00,32,00,34,\ 00,2d,00,41,00,45,00,35,00,37,00,2d,00,30,00,46,00,42,00,42,00,41,00,34,00,\ 33,00,30,00,37,00,38,00,32,00,35,00,7d,00,22,00,00,00,22,00,7b,00,39,00,46,\ 00,34,00,35,00,44,00,41,00,44,00,36,00,2d,00,30,00,30,00,39,00,35,00,2d,00,\ 34,00,36,00,34,00,33,00,2d,00,42,00,42,00,38,00,38,00,2d,00,33,00,41,00,33,\ 00,31,00,33,00,39,00,31,00,43,00,45,00,33,00,46,00,30,00,7d,00,22,00,00,00,\ 22,00,7b,00,46,00,44,00,37,00,39,00,46,00,44,00,37,00,41,00,2d,00,44,00,46,\ 00,32,00,46,00,2d,00,34,00,38,00,44,00,33,00,2d,00,42,00,32,00,31,00,34,00,\ 2d,00,35,00,34,00,36,00,37,00,32,00,42,00,39,00,38,00,36,00,43,00,43,00,42,\ 00,7d,00,22,00,00,00,00,00 "Export"=hex(7):5c,00,44,00,65,00,76,00,69,00,63,00,65,00,5c,00,54,00,63,00,70,\ 00,69,00,70,00,5f,00,7b,00,43,00,37,00,35,00,41,00,36,00,34,00,35,00,35,00,\ 2d,00,34,00,34,00,46,00,33,00,2d,00,34,00,44,00,38,00,37,00,2d,00,41,00,41,\ 00,33,00,32,00,2d,00,36,00,30,00,42,00,41,00,41,00,43,00,32,00,30,00,39,00,\ 39,00,32,00,39,00,7d,00,00,00,5c,00,44,00,65,00,76,00,69,00,63,00,65,00,5c,\ 00,54,00,63,00,70,00,69,00,70,00,5f,00,7b,00,33,00,37,00,37,00,42,00,43,00,\ 45,00,34,00,43,00,2d,00,36,00,36,00,30,00,31,00,2d,00,34,00,41,00,32,00,34,\ 00,2d,00,41,00,45,00,35,00,37,00,2d,00,30,00,46,00,42,00,42,00,41,00,34,00,\ 33,00,30,00,37,00,38,00,32,00,35,00,7d,00,00,00,5c,00,44,00,65,00,76,00,69,\ 00,63,00,65,00,5c,00,54,00,63,00,70,00,69,00,70,00,5f,00,7b,00,39,00,46,00,\ 34,00,35,00,44,00,41,00,44,00,36,00,2d,00,30,00,30,00,39,00,35,00,2d,00,34,\ 00,36,00,34,00,33,00,2d,00,42,00,42,00,38,00,38,00,2d,00,33,00,41,00,33,00,\ 31,00,33,00,39,00,31,00,43,00,45,00,33,00,46,00,30,00,7d,00,00,00,5c,00,44,\ 00,65,00,76,00,69,00,63,00,65,00,5c,00,54,00,63,00,70,00,69,00,70,00,5f,00,\ 7b,00,46,00,44,00,37,00,39,00,46,00,44,00,37,00,41,00,2d,00,44,00,46,00,32,\ 00,46,00,2d,00,34,00,38,00,44,00,33,00,2d,00,42,00,32,00,31,00,34,00,2d,00,\ 35,00,34,00,36,00,37,00,32,00,42,00,39,00,38,00,36,00,43,00,43,00,42,00,7d,\ 00,00,00,00,00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters] "ICSDomain"="mshome.net" "SyncDomainWithMembership"=dword:00000001 "NVHostname"="Leeds" "DataBasePath"=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,6f,\ 00,74,00,25,00,5c,00,53,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,\ 64,00,72,00,69,00,76,00,65,00,72,00,73,00,5c,00,65,00,74,00,63,00,00,00 "NameServer"="" "ForwardBroadcasts"=dword:00000000 "IPEnableRouter"=dword:00000000 "Domain"="" "Hostname"="Leeds" "SearchList"="" "UseDomainNameDevolution"=dword:00000001 "EnableICMPRedirect"=dword:00000001 "DeadGWDetectDefault"=dword:00000001 "DontAddDefaultGatewayDefault"=dword:00000000 "ReservedPorts"=hex(7):31,00,34,00,33,00,33,00,2d,00,31,00,34,00,33,00,34,00,\ 00,00,00,00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Adapters] [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Adapters\{377BCE4C-6601-4A24-AE57-0FBBA4307825}] "LLInterface"="" "IpConfig"=hex(7):54,00,63,00,70,00,69,00,70,00,5c,00,50,00,61,00,72,00,61,00,\ 6d,00,65,00,74,00,65,00,72,00,73,00,5c,00,49,00,6e,00,74,00,65,00,72,00,66,\ 00,61,00,63,00,65,00,73,00,5c,00,7b,00,33,00,37,00,37,00,42,00,43,00,45,00,\ 34,00,43,00,2d,00,36,00,36,00,30,00,31,00,2d,00,34,00,41,00,32,00,34,00,2d,\ 00,41,00,45,00,35,00,37,00,2d,00,30,00,46,00,42,00,42,00,41,00,34,00,33,00,\ 30,00,37,00,38,00,32,00,35,00,7d,00,00,00,00,00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Adapters\{9F45DAD6-0095-4643-BB88-3A31391CE3F0}] "LLInterface"="" "IpConfig"=hex(7):54,00,63,00,70,00,69,00,70,00,5c,00,50,00,61,00,72,00,61,00,\ 6d,00,65,00,74,00,65,00,72,00,73,00,5c,00,49,00,6e,00,74,00,65,00,72,00,66,\ 00,61,00,63,00,65,00,73,00,5c,00,7b,00,39,00,46,00,34,00,35,00,44,00,41,00,\ 44,00,36,00,2d,00,30,00,30,00,39,00,35,00,2d,00,34,00,36,00,34,00,33,00,2d,\ 00,42,00,42,00,38,00,38,00,2d,00,33,00,41,00,33,00,31,00,33,00,39,00,31,00,\ 43,00,45,00,33,00,46,00,30,00,7d,00,00,00,00,00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Adapters\{C75A6455-44F3-4D87-AA32-60BAAC209929}] "LLInterface"="" "IpConfig"=hex(7):54,00,63,00,70,00,69,00,70,00,5c,00,50,00,61,00,72,00,61,00,\ 6d,00,65,00,74,00,65,00,72,00,73,00,5c,00,49,00,6e,00,74,00,65,00,72,00,66,\ 00,61,00,63,00,65,00,73,00,5c,00,7b,00,43,00,37,00,35,00,41,00,36,00,34,00,\ 35,00,35,00,2d,00,34,00,34,00,46,00,33,00,2d,00,34,00,44,00,38,00,37,00,2d,\ 00,41,00,41,00,33,00,32,00,2d,00,36,00,30,00,42,00,41,00,41,00,43,00,32,00,\ 30,00,39,00,39,00,32,00,39,00,7d,00,00,00,00,00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Adapters\{FD79FD7A-DF2F-48D3-B214-54672B986CCB}] "LLInterface"="" "IpConfig"=hex(7):54,00,63,00,70,00,69,00,70,00,5c,00,50,00,61,00,72,00,61,00,\ 6d,00,65,00,74,00,65,00,72,00,73,00,5c,00,49,00,6e,00,74,00,65,00,72,00,66,\ 00,61,00,63,00,65,00,73,00,5c,00,7b,00,46,00,44,00,37,00,39,00,46,00,44,00,\ 37,00,41,00,2d,00,44,00,46,00,32,00,46,00,2d,00,34,00,38,00,44,00,33,00,2d,\ 00,42,00,32,00,31,00,34,00,2d,00,35,00,34,00,36,00,37,00,32,00,42,00,39,00,\ 38,00,36,00,43,00,43,00,42,00,7d,00,00,00,00,00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\DNSRegisteredAdapters] [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces] [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{377BCE4C-6601-4A24-AE57-0FBBA4307825}] "UseZeroBroadcast"=dword:00000000 "EnableDeadGWDetect"=dword:00000001 "EnableDHCP"=dword:00000000 "NameServer"="212.23.3.100,212.23.6.100" "Domain"="" "RegistrationEnabled"=dword:00000001 "RegisterAdapterName"=dword:00000000 "DhcpServer"="10.4.141.40" "Lease"=dword:00000384 "LeaseObtainedTime"=dword:48fe79fb "T1"=dword:48fe7bbd "T2"=dword:48fe7d0e "LeaseTerminatesTime"=dword:48fe7d7f "AddressType"=dword:00000000 "IsServerNapAware"=dword:00000000 "DhcpConnForceBroadcastFlag"=dword:00000001 "IPAddress"=hex(7):31,00,30,00,2e,00,30,00,2e,00,31,00,30,00,2e,00,32,00,30,00,\ 00,00,31,00,30,00,2e,00,30,00,2e,00,31,00,30,00,2e,00,31,00,39,00,00,00,31,\ 00,30,00,2e,00,30,00,2e,00,31,00,30,00,2e,00,31,00,38,00,00,00,31,00,30,00,\ 2e,00,30,00,2e,00,31,00,30,00,2e,00,31,00,37,00,00,00,31,00,30,00,2e,00,30,\ 00,2e,00,31,00,30,00,2e,00,31,00,36,00,00,00,31,00,30,00,2e,00,30,00,2e,00,\ 31,00,30,00,2e,00,31,00,35,00,00,00,31,00,30,00,2e,00,30,00,2e,00,31,00,30,\ 00,2e,00,31,00,34,00,00,00,31,00,30,00,2e,00,30,00,2e,00,31,00,30,00,2e,00,\ 31,00,33,00,00,00,31,00,30,00,2e,00,30,00,2e,00,31,00,30,00,2e,00,31,00,32,\ 00,00,00,31,00,30,00,2e,00,30,00,2e,00,31,00,30,00,2e,00,31,00,31,00,00,00,\ 31,00,30,00,2e,00,30,00,2e,00,31,00,30,00,2e,00,31,00,30,00,00,00,31,00,30,\ 00,2e,00,30,00,2e,00,31,00,30,00,2e,00,39,00,00,00,31,00,30,00,2e,00,30,00,\ 2e,00,31,00,30,00,2e,00,38,00,00,00,31,00,30,00,2e,00,30,00,2e,00,31,00,30,\ 00,2e,00,37,00,00,00,31,00,30,00,2e,00,30,00,2e,00,31,00,30,00,2e,00,36,00,\ 00,00,31,00,30,00,2e,00,30,00,2e,00,31,00,30,00,2e,00,35,00,00,00,31,00,30,\ 00,2e,00,30,00,2e,00,31,00,30,00,2e,00,34,00,00,00,31,00,30,00,2e,00,30,00,\ 2e,00,31,00,30,00,2e,00,33,00,00,00,31,00,30,00,2e,00,30,00,2e,00,31,00,30,\ 00,2e,00,32,00,00,00,00,00 "SubnetMask"=hex(7):32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,32,00,35,\ 00,35,00,2e,00,30,00,00,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,\ 32,00,35,00,35,00,2e,00,30,00,00,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,\ 00,2e,00,32,00,35,00,35,00,2e,00,30,00,00,00,32,00,35,00,35,00,2e,00,32,00,\ 35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,30,00,00,00,32,00,35,00,35,00,2e,\ 00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,30,00,00,00,32,00,35,00,\ 35,00,2e,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,30,00,00,00,32,\ 00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,30,00,\ 00,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,\ 00,30,00,00,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,32,00,35,00,\ 35,00,2e,00,30,00,00,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,32,\ 00,35,00,35,00,2e,00,30,00,00,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,\ 2e,00,32,00,35,00,35,00,2e,00,30,00,00,00,32,00,35,00,35,00,2e,00,32,00,35,\ 00,35,00,2e,00,32,00,35,00,35,00,2e,00,30,00,00,00,32,00,35,00,35,00,2e,00,\ 32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,30,00,00,00,32,00,35,00,35,\ 00,2e,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,30,00,00,00,32,00,\ 35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,30,00,00,\ 00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,\ 30,00,00,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,\ 00,2e,00,30,00,00,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,32,00,\ 35,00,35,00,2e,00,30,00,00,00,32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,\ 00,32,00,35,00,35,00,2e,00,30,00,00,00,00,00 "DefaultGateway"=hex(7):31,00,30,00,2e,00,30,00,2e,00,31,00,30,00,2e,00,32,00,\ 35,00,34,00,00,00,00,00 "DefaultGatewayMetric"=hex(7):30,00,00,00,00,00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{9F45DAD6-0095-4643-BB88-3A31391CE3F0}] "UseZeroBroadcast"=dword:00000000 "EnableDeadGWDetect"=dword:00000001 "EnableDHCP"=dword:00000001 "NameServer"="" "Domain"="" "RegistrationEnabled"=dword:00000001 "RegisterAdapterName"=dword:00000000 "DhcpIPAddress"="0.0.0.0" "DhcpSubnetMask"="255.0.0.0" "DhcpServer"="255.255.255.255" "Lease"=dword:00000000 "LeaseObtainedTime"=dword:00000000 "T1"=dword:00000000 "T2"=dword:00000000 "LeaseTerminatesTime"=dword:00000000 "AddressType"=dword:00000000 "IsServerNapAware"=dword:00000000 "DhcpConnForceBroadcastFlag"=dword:00000001 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{C75A6455-44F3-4D87-AA32-60BAAC209929}] "UseZeroBroadcast"=dword:00000000 "EnableDeadGWDetect"=dword:00000001 "EnableDHCP"=dword:00000000 "NameServer"="192.168.1.254" "Domain"="" "RegistrationEnabled"=dword:00000001 "RegisterAdapterName"=dword:00000000 "DhcpServer"="255.255.255.255" "Lease"=dword:00093a80 "LeaseObtainedTime"=dword:490ecd1c "T1"=dword:49136a5c "T2"=dword:4916e04c "LeaseTerminatesTime"=dword:4918079c "AddressType"=dword:00000000 "IsServerNapAware"=dword:00000000 "DhcpConnForceBroadcastFlag"=dword:00000001 "IPAddress"=hex(7):31,00,39,00,32,00,2e,00,31,00,36,00,38,00,2e,00,31,00,2e,00,\ 32,00,30,00,00,00,00,00 "SubnetMask"=hex(7):32,00,35,00,35,00,2e,00,32,00,35,00,35,00,2e,00,32,00,35,\ 00,35,00,2e,00,30,00,00,00,00,00 "DefaultGateway"=hex(7):31,00,39,00,32,00,2e,00,31,00,36,00,38,00,2e,00,31,00,\ 2e,00,32,00,35,00,34,00,00,00,00,00 "DefaultGatewayMetric"=hex(7):30,00,00,00,00,00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{FD79FD7A-DF2F-48D3-B214-54672B986CCB}] "UseZeroBroadcast"=dword:00000000 "EnableDeadGWDetect"=dword:00000001 "EnableDHCP"=dword:00000001 "NameServer"="" "Domain"="" "RegistrationEnabled"=dword:00000001 "RegisterAdapterName"=dword:00000000 "DhcpIPAddress"="0.0.0.0" "DhcpSubnetMask"="255.0.0.0" "DhcpServer"="255.255.255.255" "Lease"=dword:00000000 "LeaseObtainedTime"=dword:00000000 "T1"=dword:00000000 "T2"=dword:00000000 "LeaseTerminatesTime"=dword:00000000 "AddressType"=dword:00000000 "IsServerNapAware"=dword:00000000 "DhcpConnForceBroadcastFlag"=dword:00000001 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\PersistentRoutes] "0.0.0.0,0.0.0.0,192.168.1.254,-1"="" "0.0.0.0,0.0.0.0,10.0.10.254,-1"="" [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Winsock] "HelperDllName"=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,\ 6f,00,74,00,25,00,5c,00,53,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,\ 00,77,00,73,00,68,00,74,00,63,00,70,00,69,00,70,00,2e,00,64,00,6c,00,6c,00,\ 00,00 "MaxSockAddrLength"=dword:00000010 "MinSockAddrLength"=dword:00000010 "Mapping"=hex:08,00,00,00,03,00,00,00,02,00,00,00,01,00,00,00,06,00,00,00,02,\ 00,00,00,01,00,00,00,00,00,00,00,02,00,00,00,00,00,00,00,06,00,00,00,02,00,\ 00,00,02,00,00,00,11,00,00,00,02,00,00,00,02,00,00,00,00,00,00,00,02,00,00,\ 00,00,00,00,00,11,00,00,00,02,00,00,00,03,00,00,00,ff,00,00,00,02,00,00,00,\ 03,00,00,00,00,00,00,00 "UseDelayedAcceptance"=dword:00000000 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Performance] "Close"="CloseTcpIpPerformanceData" "Collect"="CollectTcpIpPerformanceData" "Library"="Perfctrs.dll" "Open"="OpenTcpIpPerformanceData" "ObjectList"="502510546548582638658153015321534" [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\ServiceProvider] "Class"=dword:00000008 "DnsPriority"=dword:000007d0 "HostsPriority"=dword:000001f4 "LocalPriority"=dword:000001f3 "Name"="TCP/IP" "NetbtPriority"=dword:000007d1 "ProviderPath"=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,6f,\ 00,74,00,25,00,5c,00,53,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,\ 77,00,73,00,6f,00,63,00,6b,00,33,00,32,00,2e,00,64,00,6c,00,6c,00,00,00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Enum] "0"="Root\\LEGACY_TCPIP\\0000" "Count"=dword:00000001 "NextInstance"=dword:00000001 CheersCraig.

hi craig,can you please setDhcpConnForceBroadcastFlag to 0 / delete the entry ? for testing and also make sure that your dhcp server field is also deleted , i see 255.255.255.255 , please clear the values of the registry and delete theDhcpConnForceBroadcastFlag and perform repairyou have to delete dhcpconnforcebroadcastflag for 3 interfaces which are listed in your log . if above procedure/ troubleshooting did not help , please follow the below stepsReset WINSOCK entries to installation defaults: netsh winsock reset catalogReset IPv4 TCP/IP stack to installation defaults. netsh int ipv4 reset reset.logReset IPv6 TCP/IP stack to installation defaults. netsh int ipv6 reset reset.logsainath Windows Driver Development

HiSorry it's been so long since we picked this up but looking into it had to get sidelined.Thanks for the suggestions sainath but unfortunately that's not something we can really try at present. The server is several hours drive away and obviously editing the registry remotely isn't something we want to start doing, plus it's heavily relied on.Is there anything else we could look atfor a potentially"easier" fix? I appreciate it's a complicated problem so it's unlikely. If it comes to us having no choice but to send someone up there, thenI suppose that's what we'll have to do.CheersCraig.

I'm having the same issue here. Server is Windows 2008 SP1 64bit We have 21 IP's of one subnet on nic0 and 1 ip of another subnet on nic1 After a reboot the subnet mask of the 21 ip's changed from 255.255.255.224 to 255.255.255.255 We also don't use DHCP Is this a known issue by now ? Pieter

Craig, I've opened a case with MS to get this sorted out. Looks like in SP1 this is an issue, causing loss of connectivity. In SP2, this issue is only cosmetic in th GUI. It might have been fixed in R2, but that is unconfirmed. to be continued... Pieter

How do you reboot your server? What's the procedure that you follow? A faulty network card is a possibility. However try this first. Open the Registry (on your server) at HKLM\System\CurrentControlset\Services\Tcpip\Parameters\Interfaces\ (your connection for your network) Insert a new REG_MULTI_SZ string value named "DhcpSubnetMaskOpt" (without the quotes) Give it the same value as your preferred subnet mask i.e 255.255.255.0 These values should all match your Router's subnet setting, which should be saved as the default for the router (wireless or otherwise) Consider the following scenario. IF THE ROUTER IS 192.168.1.1 YOUR SERVER 192.168.1.102 (ASSIGNED BY THE ROUTER) With the router "max Connections specified to 254) If you want more then the subnet mask's third octet will need shrinking accordingly. Take the router off line, then reboot the server. When the server has booted and resettled - about ten minutes - bring the router back on line, wait a few minutes, then everyone log back in. (This particular procedure is designed to give a field isolation check for any possible hardware problems - See below) Unless the NIC is faulty or (along with the router) and or require a firmware revision, this should hopefully solve your problem. (There is a very rare chance that it might be a faulty cable between your Server and Router) Switch offs and ons can sometimes set up voltage spikes causing resets due to stray capacitance between poor terminations either inside or at the ends of the cables. Very rare - but has happened to me "once"! Running an integrity check between your NIC, Server and router and should be the first call. Your cabling especially should be the best you can get. If they trail in areas of high voltage relays, cables or other sources of electromagnetic interfernce, consider, suppression baluns threaded over power cables and fully shielded comms cables. Nick "Life is for the uninitiated - how else do we learn"

I have recently experienced this issue with two of our web servers running Windows 2008 Std SP2. After reboot, the subnet mask for all my ip addresses was changed to 255.255.255.255 which caused production outages. Has anyone found the root cause of this issue yet?

Theizer Did you ever find out the root cause of your issue with this? Thank you,

Much later, but I'm having this issue. Did anyone ever get this resolved?