请问Socket中控制端口与数据端口的区别,

[iris_福将]

各位高手!
初编网络程序,遇到了麻烦,不知该如何解决.
我用ClientSocket控件,已知ip地址、控制端口号＝5000、用户名和口令,连接到服务器后，服务器端发送8002为数据端口，通知我连接到数据端口，我不知该如何连？
帮帮我！

[Y___Y]

一般搞一个端口进行通讯就可以了
非要搞两个就用两个ClientSocket对象

[iris_福将]

我没有弄懂的是：5000为控制端口，服务器端数据口为8002，它们是什么关系？我的连接方法对吗？

void __fastcall TForm1::connectClick(TObject *Sender)
{
char tmp[20];

Form2->ShowModal();
strcpy(hostname,Form2->ComboBox1->Text.c_str());
strcpy(portserv,Form2->portN->Text.c_str());

if (ClientSocket1->Active)
{
ClientSocket1->Active = false;
}

ClientSocket1->Host= hostname;
ClientSocket1->Port=atoi(portserv);
ClientSocket1->Active = true;

char *buf=(char *)malloc(ClientSocket1->Socket->ReceiveLength()+1);
memset(buf,0x00,ClientSocket1->Socket->ReceiveLength()+1);
ClientSocket1->Socket->ReceiveBuf(buf,ClientSocket1->Socket->ReceiveLength()+1); //接收 "100 connection accepted login:\r\n"
strcpy(tmp,Form2->userN->Text.c_str()); //user name
strcat(tmp,"\r\n");
ClientSocket1->Socket->SendBuf(tmp,strlen(tmp)); //发送 用户名
Memo1->Lines->Add(buf);
::Sleep(200);
memset(buf,0x00,ClientSocket1->Socket->ReceiveLength()+1);
ClientSocket1->Socket->ReceiveBuf(buf,ClientSocket1->Socket->ReceiveLength()+1); //接收 "102 password for:\r\n"
strcpy(tmp,Form2->passW->Text.c_str()); //pass word
strcat(tmp,"\r\n");
ClientSocket1->Socket->SendBuf(tmp,strlen(tmp));//发送 口令
Memo1->Lines->Add(buf);
memset(buf,0x00,ClientSocket1->Socket->ReceiveLength()+1);
::Sleep(200);
ClientSocket1->Socket->ReceiveBuf(buf,ClientSocket1->Socket->ReceiveLength()+1); //接收 "107 check passed to create data link.\r\n
//Memo1->Lines->Add(buf);
sscanf(buf,"%3s",tmp);
if(strcmp(tmp,"107")!=0)
goto lab1;
strcpy(tmp,Form2->portN->Text.c_str());
strcat(tmp,"\r\n");
::Sleep(200);
ClientSocket1->Socket->SendBuf(tmp,strlen(tmp));
memset(buf,0x00,ClientSocket1->Socket->ReceiveLength()+1);
::Sleep(200);
ClientSocket1->Socket->ReceiveBuf(buf,ClientSocket1->Socket->ReceiveLength()+1); //接收 "108 8002 is data port.\r\n"
//以上步骤接发都正确，再往下还需要再连到数据端口8002？我不知该怎样做了。
::Sleep(200);
memset(buf,0x00,ClientSocket1->Socket->ReceiveLength()+1);
::Sleep(200);
ClientSocket1->Socket->ReceiveBuf(buf,1200);
}