Dynamically changing TCP/IP DNS addresses

If you connect to the Internet, a Domain Name Server (DNS) is generally required to convert English Internet addresses to their natural numeric IP addresses -- to convert www.chami.com to 1.2.3.4 for example.

If you have a need to dynamically change your DNS servers from your program, you can do so by calling the the following "SetTCPIPDNSAddresses()" function with a list of DNS IP addresses separated by a single space.

Listing #1 : Delphi code.
uses Registry;

procedure
SaveStringToRegistry_LOCAL_MACHINE(
sKey, sItem, sVal : string );
var
reg : TRegIniFile;
begin
reg := TRegIniFile.Create( '' );
reg.RootKey := HKEY_LOCAL_MACHINE;
reg.WriteString(
sKey, sItem, sVal + #0 );
reg.Free;
end;

Listing #2 : Delphi code.
procedure
SetTCPIPDNSAddresses(
sIPs : string );
begin
//
// if using Windows NT
//
SaveStringToRegistry_LOCAL_MACHINE(
'SYSTEMCurrentControlSet' +
'ServicesTcpipParameters',
'NameServer',
sIPs );

//
// if using Windows 95
//
SaveStringToRegistry_LOCAL_MACHINE(
'SYSTEMCurrentControlSet' +
'ServicesVxDMSTCP',
'NameServer',
sIPs );
end;

For example, if you want to set two DNS server addresses -- 1.2.3.4 and 5.6.7.8 here's how your function call would look like:

Listing #3 : Delphi code.
SetTCPIPDNSAddresses(
'1.2.3.4 5.6.7.8' );