使用WinSock控件连接对方的IP和端口,然后在Winsock的"Sub Winsock_Connect()"事件中判断是否能连接上,能连接上则此端口是开放的：

{{
'Form1:控件:Timer,名:Timer1,Interval:1000
'控件:Winsock,名:Winsock1;

Option Explicit

Dim F_PortScan As Long

Private Sub Timer1_Timer()
F_PortScan = F_PortScan + 1

Winsock1.Close
Winsock1.RemoteHost = "60.7.81.12" '要扫描的IP
Winsock1.RemotePort = F_PortScan '要扫描的端口
Winsock1.Connect '开始连接
Form1.Caption = "正在扫描端口:" & F_PortScan

End Sub

Private Sub Winsock1_Connect() '如果连接上
MsgBox F_PortScan & "端口开放"
End Sub

}}

from:http://zhidao.baidu.com/question/44579979.html?fr=qrl&fr2=query