WMI Tasks using Delphi – Networking

How do I disable a network connection using WMI?

If you are using DHCP, use the Win32_NetworkAdapterConfiguration and the ReleaseDHCPLease method to release the IP address. If you are not using DHCP, you cannot use WMI to disable a network connection. To re-enable the network connection, use objNetCard.RenewDHCPLease. You can also release or renew all of the DHCP leases using the ReleaseDHCPLeaseAll and RenewDHCPLeaseAll methods.

const
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
begin;
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT * FROM Win32_NetworkAdapterConfiguration Where IPEnabled = True','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  while oEnum.Next(1, FWbemObject, iValue) = 0 do
  begin
    FWbemObject.ReleaseDHCPLease();
    FWbemObject:=Unassigned;
  end;
end;

How do I disable or enable a NIC?

Use the Win32_NetworkAdapter class and the Disable or Enable methods.

//Disable a NIC
const
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
begin;
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT * FROM Win32_NetworkAdapter Where NetEnabled=True','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  while oEnum.Next(1, FWbemObject, iValue) = 0 do
  begin
    FWbemObject.Disable();
    FWbemObject:=Unassigned;
  end;
end;

//Enable a NIC
const
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
begin;
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT * FROM Win32_NetworkAdapter Where NetEnabled=False','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  while oEnum.Next(1, FWbemObject, iValue) = 0 do
  begin
    FWbemObject.Enable();
    FWbemObject:=Unassigned;
  end;
end;

How do I determine which IP address has been assigned to a given network connection?

Use the Win32_NetworkAdapter class and the NetConnectionID property to determine the MAC address of the network connection. Then, use the Win32_NetworkAdapterConfiguration class to find the IP address associated with the MAC address.

const
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
  strMACAddress : string;
  i             : Integer;
begin;
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');

  FWbemObjectSet:= FWMIService.ExecQuery(Format('SELECT MACAddress FROM Win32_NetworkAdapter Where NetConnectionID="%s"',['Local Area Connection 2']),'WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  if oEnum.Next(1, FWbemObject, iValue) = 0 then
  begin
    strMACAddress:=String(FWbemObject.MACAddress);
    FWbemObject:=Unassigned;
  end;

  FWbemObjectSet:= FWMIService.ExecQuery(Format('SELECT IPAddress FROM Win32_NetworkAdapterConfiguration Where MACAddress="%s"',[strMACAddress]),'WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  if oEnum.Next(1, FWbemObject, iValue) = 0 then
  begin
    if not VarIsClear(FWbemObject.IPAddress) then
    for i := VarArrayLowBound(FWbemObject.IPAddress, 1) to VarArrayHighBound(FWbemObject.IPAddress, 1) do
     Writeln(Format('IP Address %s',[String(FWbemObject.IPAddress[i])]));
    FWbemObject:=Unassigned;
  end;
end;

How do I determine the MAC address of a network adapter?

Use the Win32_NetworkAdapterConfiguration class and check the value of the MACAddress property.

const
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
begin;
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT Description,MACAddress FROM Win32_NetworkAdapterConfiguration','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  while oEnum.Next(1, FWbemObject, iValue) = 0 do
  begin
    Writeln(Format('Description %s',[String(FWbemObject.Description)]));
    if not VarIsNull(FWbemObject.MACAddress) then
      Writeln(Format('  MAC Address %s',[String(FWbemObject.MACAddress)]))
    else
      Writeln(Format('  MAC Address %s',['Empty']));
    FWbemObject:=Unassigned;
  end;
end;

How do I determine the IP address(es) of a computer?

Use the Win32_NetworkAdapterConfiguration class and check the value of the IPAddress property.

const
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
  i             : Integer;
begin;
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT IPAddress FROM Win32_NetworkAdapterConfiguration','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  while oEnum.Next(1, FWbemObject, iValue) = 0 do
  begin
    if not VarIsClear(FWbemObject.IPAddress) and not VarIsNull(FWbemObject.IPAddress) then
    for i := VarArrayLowBound(FWbemObject.IPAddress, 1) to VarArrayHighBound(FWbemObject.IPAddress, 1) do
     Writeln(Format('IP Address %s',[String(FWbemObject.IPAddress[i])]));
    FWbemObject:=Unassigned;
  end;
end;

How do I configure a computer to start getting its IP address through DHCP?

Use the Win32_NetworkAdapterConfiguration class and the EnableDHCP method.

const
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
begin
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT * FROM Win32_NetworkAdapterConfiguration Where IPEnabled=True','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  while oEnum.Next(1, FWbemObject, iValue) = 0 do
  begin
    FWbemObject.EnableDHCP();
    FWbemObject:=Unassigned;
  end;
end;

How do I assign a computer a static IP address?

Use the Win32_NetworkAdapterConfiguration class and the EnableStatic method.

function ArrayToVarArray(Arr : Array Of string):OleVariant; overload;
var
 i : integer;
begin
    Result   :=VarArrayCreate([0, High(Arr)], varVariant);
    for i:=Low(Arr) to High(Arr) do
     Result[i]:=Arr[i];
end;

function ArrayToVarArray(Arr : Array Of Word):OleVariant;overload;
var
 i : integer;
begin
    Result   :=VarArrayCreate([0, High(Arr)], varVariant);
    for i:=Low(Arr) to High(Arr) do
     Result[i]:=Arr[i];
end;

procedure  SetStaticIP;
const
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
  vIPAddress         : OleVariant;
  vSubnetMask        : OleVariant;
  vDefaultIPGateway  : OleVariant;
  vGatewayCostMetric : OleVariant;
begin
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT * FROM Win32_NetworkAdapterConfiguration Where IPEnabled=True','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  while oEnum.Next(1, FWbemObject, iValue) = 0 do
  begin
    vIPAddress   := ArrayToVarArray(['192.168.1.141']);
    vSubnetMask  := ArrayToVarArray(['255.255.255.0']);
    if FWbemObject.EnableStatic(vIPAddress, vSubnetMask) = 0 then
    begin
      vDefaultIPGateway  := ArrayToVarArray(['192.168.1.100']);
      vGatewayCostMetric := ArrayToVarArray([1]);
      FWbemObject.SetGateways(vDefaultIPGateway,vGatewayCostMetric);
    end;

    VarClear(vIPAddress);
    VarClear(vSubnetMask);
    VarClear(vDefaultIPGateway);
    VarClear(vGatewayCostMetric);
    FWbemObject:=Unassigned;
  end;
end;

How do I ping a computer without using Ping.exe?

Use the Win32_PingStatus class. Starting with Windows Vista, Win32_PingStatus can return data for computers that have both IPv4 addresses and IPv6 addresses.

For a delphi sample code check this article Making a PING with Delphi and the WMI.

This post is based in the MSDN entry WMI Tasks: Networking

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