Dynamically changing TCP/IP DNS addresses

See Also

• Creating new domain names (for personal use) (Internet tip)

• How to connect two computers and access their drives through the Internet (Windows tip)

• What class should my TCP/IP network be? (Internet tip)

• Who's connected to you? (Windows tip)

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.

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 #1 : Delphi code. Right click registry.pas to download.

procedure

SetTCPIPDNSAddresses(

sIPs : string );

begin

//

// if using Windows NT

//

SaveStringToRegistry_LOCAL_MACHINE(

'SYSTEM\CurrentControlSet' +

'\Services\Tcpip\Parameters',

'NameServer',

sIPs );

//

// if using Windows 95

//

SaveStringToRegistry_LOCAL_MACHINE(

'SYSTEM\CurrentControlSet' +

'\Services\VxD\MSTCP',

'NameServer',

sIPs );

end;

Listing #2 : Delphi code. Right click setdns.pas to download.

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:

SetTCPIPDNSAddresses(

'1.2.3.4 5.6.7.8' );