如何检查远程端口是否打开

Question

创建Windows应用程序以检查与少数服务器的连接。如何检查天气是否存在与远程ip上指定端口的连接？

是否有任何Windows内置命令来检查远程端口（命令行）？

检查前不知道天气端口是TCP还是UDP端口。怎么可能。

在此先感谢

Answer 1

从我的（德国）博客：enter link description here

更新：该工具支持UDP端口和多端口平现在太。

如果端口打开，它将返回true。这是老式的代码（没有TPL），但它的工作原理。

var result = false; 
using (var client = new TcpClient()) 
{ 
    try 
    { 
     client.ReceiveTimeout = timeout * 1000; 
     client.SendTimeout = timeout * 1000; 
     var asyncResult = client.BeginConnect(host, port, null, null); 
     var waitHandle = asyncResult.AsyncWaitHandle; 
     try 
     { 
      if (!asyncResult.AsyncWaitHandle.WaitOne(TimeSpan.FromSeconds(timeout), false)) 
      { 
       // wait handle didn't came back in time 
       client.Close(); 
      } 
      else 
      { 
       // The result was positiv 
       result = client.Connected; 
      } 
      // ensure the ending-call 
      client.EndConnect(asyncResult); 
     } 
     finally 
     { 
      // Ensure to close the wait handle. 
      waitHandle.Close(); 
     } 
    } 
    catch 
    { 
    } 
} 
return result;