使用System.Net命名空间对网络进行操作

利用IPHostEntry类的GetHostByName方法，可以根据机器名来找到该机器的IP地址。

using  System.Net;

     protected   void  mybutton_Click( object  sender, EventArgs e)
    {
        IPHostEntry hostInfo  =  Dns.GetHostByName(txtDomain.Text);
        showmsg.Text  =  hostInfo.HostName;
    }

     < form id = " form1 "  runat = " server " >
     < div >
         < asp:Label ID = " showmsg "  runat = " server "  Width = " 229px " ></ asp:Label >< br  />
        请输入机器名： < asp:TextBox ID = " txtDomain "  runat = " server " ></ asp:TextBox >
         < asp:Button ID = " mybutton "  runat = " server "  OnClick = " mybutton_Click "  Text = " 确定 "   /></ div >
     </ form >

利用IPHostEntry类的GetHostByAddress方法，可以根据IP地址来找到该机器名。

using  System.Net;

         protected void mybutton_Click(object sender, EventArgs e)
    {
        IPHostEntry hostInfo = Dns.GetHostByAddress(txtDomain.Text);
        showmsg.Text = hostInfo.HostName;
    }

     < form id = " form1 "  runat = " server " >
     < div >
         < asp:Label ID = " showmsg "  runat = " server "  Width = " 229px " ></ asp:Label >< br  />
        请输入机器名： < asp:TextBox ID = " txtDomain "  runat = " server " ></ asp:TextBox >
         < asp:Button ID = " mybutton "  runat = " server "  OnClick = " mybutton_Click "  Text = " 确定 "   /></ div >
     </ form >

检测服务器开放的端口信息

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

protected   void  Page_Load( object  sender, EventArgs e)
    {
         int [] arrPort  =   new   int [ 5 ] {  21 ,  23 ,  25 ,  110 ,  1433  };
         string  strServer  =   " localhost " ;
         string  strService, strResponse, strShow;
         int  intport;
         for  ( int  i  =   0 ; i  <  arrPort.Length; i ++ )
        {
            intport  =  arrPort[i];
             switch  (intport)
            {
                 case   21 :
                    strService  =   " FTP服务 " ;
                     break ;
                 case   23 :
                    strService  =   " Telnet服务 " ;
                     break ;
                 case   25 :
                    strService  =   " SMTP服务 " ;
                     break ;
                 case   110 :
                    strService  =   " POP3服务 " ;
                     break ;
                 default :
                    strService  =   " 无法知道 " ;
                     break ;
            }
             if  ((strResponse  =  TcpConnect(strServer, intport))  !=   " 没有开放 " )
            {
                strShow  =   " <b> "   +  intport.ToString()  +   " </b>端口:  "   +
                    strResponse  +   " (<font color=red> "   +  strService  +   " </font>) " ;
            }
             else
            {
                strShow  =   " <b> "   +  intport.ToString()  +   " </b>端口没有开放:  "  
                     +   " (<font color=red> "   +  strService  +   " </font>) " ;
            }
            pnlServer.Controls.Add( new  LiteralControl(strShow  +   " <p> " ));
        }
    }

     public   string  TcpConnect( string  strServer,  int  intPort)
    {
         string  strResult;
        TcpClient tcpc  =   new  TcpClient();
         try
        {
            tcpc.Connect(strServer, intPort);
            Stream s  =  tcpc.GetStream();
            StreamReader sr  =   new  StreamReader(s, System.Text.Encoding.Default);
            strResult  =  sr.ReadLine();
        }
         catch  (Exception ee)
        {
            strResult  =   " 没有开放 " ;
        }
         finally
        {
            tcpc.Close();
        }
         return  strResult;            
    }

     < form id = " form1 "  runat = " server " >
     < div >
        使用Socket探测主机信息 < br  />
         < asp:Panel ID = " pnlServer "  runat = " server "  Height = " 254px "  Width = " 400px " >
         </ asp:Panel >
     </ div >
     </ form >