How to determine if an IP address is DHCP assigned?

Archived from groups: microsoft.public.windowsnt.protocol.tcpip,microsoft.public.win32.programmer.networks (More info?)

Wei Wang wrote:
> (Apologies for the cross-posting as I am still new to the Microsoft
> groups.)
> The situation is that, an interface (say an Ethernet LAN connection)
> may have multiple IP addresses. When DHCP is enabled on the
> interface, what is the best way to determine if a particular IP address is
> DHCP
> assigned?
> What I have done so far is traversing the IP address table returned by
> the GetIpAddrTable() function, then check the (dwType) field in each
> MIB_IPADDRROW entry for the MIB_IPADDR_DYNAMIC bit.

Did you try GetAdaptersAddresses? It is not available on Win2k though.


--
Eugene
http://www.gershnik.com

Archived from groups: microsoft.public.windowsnt.protocol.tcpip,microsoft.public.win32.programmer.networks (More info?)

Eugene Gershnik wrote:
> Wei Wang wrote:
>
>>(Apologies for the cross-posting as I am still new to the Microsoft
>>groups.)
>>The situation is that, an interface (say an Ethernet LAN connection)
>>may have multiple IP addresses. When DHCP is enabled on the
>>interface, what is the best way to determine if a particular IP address is
>>DHCP
>>assigned?
>>What I have done so far is traversing the IP address table returned by
>>the GetIpAddrTable() function, then check the (dwType) field in each
>>MIB_IPADDRROW entry for the MIB_IPADDR_DYNAMIC bit.
>
>
> Did you try GetAdaptersAddresses? It is not available on Win2k though.

Thanks a lot for responding. I did look at it. But it didn't seem to
provide the information I need.

Have I missed anything in what that function does? I looked a bit deeper
just now. The IP_ADAPTER_UNICAST_ADDRESS described on is page seems
promising:

http://msdn.microsoft.com/library/default.asp?url=/libr...

I will try to write some code to see what I get back for different kinds
of addresses. However, from reading the information on the page above,
there is no direct indication either. The only thing I could do seems to
check (ValidLifetime) and (LeaseLifetime). However, what should I expect
to see in there for DHCP address and otherwise?

Again, thanks for responding.
--
Wei Wang

Archived from groups: microsoft.public.windowsnt.protocol.tcpip,microsoft.public.win32.programmer.networks (More info?)

You can read it from registry or check it with WMI
Arkady

"Wei Wang" <ww9rivers@gmail.com> wrote in message
news:4317CF70.7020800@gmail.com...
> Eugene Gershnik wrote:
>> Wei Wang wrote:
>>
>>>(Apologies for the cross-posting as I am still new to the Microsoft
>>>groups.)
>>>The situation is that, an interface (say an Ethernet LAN connection)
>>>may have multiple IP addresses. When DHCP is enabled on the
>>>interface, what is the best way to determine if a particular IP address
>>>is DHCP
>>>assigned?
>>>What I have done so far is traversing the IP address table returned by
>>>the GetIpAddrTable() function, then check the (dwType) field in each
>>>MIB_IPADDRROW entry for the MIB_IPADDR_DYNAMIC bit.
>>
>>
>> Did you try GetAdaptersAddresses? It is not available on Win2k though.
>
> Thanks a lot for responding. I did look at it. But it didn't seem to
> provide the information I need.
>
> Have I missed anything in what that function does? I looked a bit deeper
> just now. The IP_ADAPTER_UNICAST_ADDRESS described on is page seems
> promising:
>
> http://msdn.microsoft.com/library/default.asp?url=/libr...
>
> I will try to write some code to see what I get back for different kinds
> of addresses. However, from reading the information on the page above,
> there is no direct indication either. The only thing I could do seems to
> check (ValidLifetime) and (LeaseLifetime). However, what should I expect
> to see in there for DHCP address and otherwise?
>
> Again, thanks for responding.
> --
> Wei Wang

Archived from groups: microsoft.public.windowsnt.protocol.tcpip,microsoft.public.win32.programmer.networks (More info?)

Arkady Frenkel wrote:
> You can read it from registry or check it with WMI

Mind sharing some details?

Thanks for responding.
--
Wei Wang

Archived from groups: microsoft.public.windowsnt.protocol.tcpip,microsoft.public.win32.programmer.networks (More info?)

EnableDHCP key for my adapter guid
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{2CA46387-EE75-49C2-A468-9CA7CE69DC65}\Parameters\Tcpip
Arkady

"Wei Wang" <ww9rivers@gmail.com> wrote in message
news:43204898.3070409@gmail.com...
> Arkady Frenkel wrote:
>> You can read it from registry or check it with WMI
>
> Mind sharing some details?
>
> Thanks for responding.
> --
> Wei Wang

Archived from groups: microsoft.public.windowsnt.protocol.tcpip,microsoft.public.win32.programmer.networks (More info?)

Thanks for responding.

Arkady Frenkel wrote:
> EnableDHCP key for my adapter guid
> HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{2CA46387-EE75-49C2-A468-9CA7CE69DC65}\Parameters\Tcpip

I checked. But those registry entries do not have information on
multiple IP addresses on a single interface.

By the way, the term "IP aliasing" means to add more than one IP address
to an interface:

http://www.defcon1.org/html/Networking_Articles/natdhow...

Regards,
--
Wei Wang

Archived from groups: microsoft.public.windowsnt.protocol.tcpip,microsoft.public.win32.programmer.networks (More info?)

But those by definition not have DHCP ( as Eugene wrote ) , you set IP , not
DHCP so DHCP know nothing about them and can't know
Arkady

"Wei Wang" <ww9rivers@gmail.com> wrote in message
news:4320580F.8090308@gmail.com...
> Thanks for responding.
>
> Arkady Frenkel wrote:
>> EnableDHCP key for my adapter guid
>> HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{2CA46387-EE75-49C2-A468-9CA7CE69DC65}\Parameters\Tcpip
>
> I checked. But those registry entries do not have information on multiple
> IP addresses on a single interface.
>
> By the way, the term "IP aliasing" means to add more than one IP address
> to an interface:
>
> http://www.defcon1.org/html/Networking_Articles/natdhow...
>
> Regards,
> --
> Wei Wang