const
MAX_HOSTNAME_LEN = 128;
MAX_DOMAIN_NAME_LEN = 128;
MAX_SCOPE_ID_LEN = 256;
type
//
// TIPAddressString - store an IP address or mask as dotted decimal string
//
PIPAddressString = ^TIPAddressString;
PIPMaskString = ^TIPAddressString;
TIPAddressString =
record
_String:
array[0..(4 * 4) - 1]
of Char;
end;
TIPMaskString = TIPAddressString;
//
// TIPAddrString - store an IP address with its corresponding subnet mask,
// both as dotted decimal strings
//
PIPAddrString = ^TIPAddrString;
TIPAddrString =
packed record
Next: PIPAddrString;
IpAddress: TIPAddressString;
IpMask: TIPMaskString;
Context: DWORD;
end;
//
// FIXED_INFO - the set of IP-related information which does not depend on DHCP
//
PFixedInfo = ^TFixedInfo;
TFixedInfo =
packed record
HostName:
array[0..MAX_HOSTNAME_LEN + 4 - 1]
of Char;
DomainName:
array[0..MAX_DOMAIN_NAME_LEN + 4 - 1]
of Char;
CurrentDnsServer: PIPAddrString;
DnsServerList: TIPAddrString;
NodeType: UINT;
ScopeId:
array[0..MAX_SCOPE_ID_LEN + 4 - 1]
of Char;
EnableRouting,
EnableProxy,
EnableDns: UINT;
end;
function GetNetworkParams(pFixedInfo: PFixedInfo; pOutBufLen: PULONG): DWORD;
stdcall;
// Get machine DNS Servers and return them in the provided StringList. This list should have been
// already created by the calling program before performing this call
procedure GetDNSServers(AList: TStrings);
implementation
{$R *.DFM}
function GetNetworkParams;
external '
iphlpapi.dll'
Name '
GetNetworkParams';
procedure GetDNSServers(AList: TStrings);
var
pFI: PFixedInfo;
pIPAddr: PIPAddrString;
OutLen: Cardinal;
begin
AList.Clear;
pFI:=nil;
OutLen :=0;
OutLen := SizeOf(TFixedInfo);
GetMem(pFI, SizeOf(TFixedInfo));
try
if GetNetworkParams(pFI, @OutLen) = ERROR_BUFFER_OVERFLOW
then
begin
ReallocMem(pFI, OutLen);
if GetNetworkParams(pFI, @OutLen) <> NO_ERROR
then Exit;
end;
// If there is no network available there may be no DNS servers defined
if pFI^.DnsServerList.IpAddress._String[0] = #0
then Exit;
// Add first server
// alist.Add(pFI^.DnsServerList.IpAddress._String);
AList.Add(pFI^.DnsServerList.IpAddress._String);
// Add rest of servers
pIPAddr := pFI^.DnsServerList.Next;
while Assigned(pIPAddr)
do
begin
AList.Add(pIPAddr^.IpAddress._String);
pIPAddr := pIPAddr^.Next;
end;
finally
FreeMem(pFI);
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
GetDnsServers(listbox1.items);
end;