C#快速判断网络端口连通状态

using System.Net.Sockets;
using System.Net;

//完成TELNET
private static string cmdTelnet(string strIP,int strNum)
{
string strTelnet;

try
{
IPAddress ip = IPAddress.Parse(strIP);
IPEndPoint point = new IPEndPoint(ip, strNum);
Socket sock = new Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp);
sock.Connect(point);
strTelnet = string.Format("连接端口{0} 成功!",point);
}
catch(SocketException e)
{
if (e.ErrorCode != 10061)
{
MessageBox.Show(e.Message.ToString(), "提示", MessageBoxButtons.OK);
}
strTelnet = string.Format("连接{0} 失败", strIP + ":" + strNum);
}
return strTelnet;
}