VB.NET ping端口

Question

我試圖做一個服務器狀態檢查器，可以在端口上ping通。

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load 
    If My.Computer.Network.Ping("192.168.2.10:21") Then 
     PictureBox1.BackColor = Color.LimeGreen 
     Label1.Text = "Online!" 
     Label1.ForeColor = Color.LimeGreen 

    Else 
     PictureBox1.BackColor = Color.DarkRed 
     Label1.Text = "Offline!" 
     Label1.ForeColor = Color.DarkRed 
    End If 
End Sub 

當我這樣做，它不會返回任何結果。沒有離線或在線。

Answer 1

正如我在評論中指出的那樣，ping與端口將不起作用。因此，您只能檢查遠程可用性。並與"ipaddress:port"寫作應該拋出錯誤

平通過發送Internet控制消息協議（ICMP）

其他方式這樣做的工作是使用TCP

在這裏，我寫了ping命令正確方法端口和Neetwork.Ping

Private Function checkport(hostname As String, port As Integer 
          ) As Boolean 
    Dim client As New TcpClient(AddressFamily.InterNetwork) 


    client.BeginConnect(hostname, port, 
         Sub(x) 
          Dim tcp As TcpClient = CType(x.AsyncState, TcpClient) 
          Try 
           tcp.EndConnect(x) 
           SetIndicators(True) 

          Catch ex As Exception 
           'error 
           SetIndicators(False) 

          End Try 
          tcp.Close() 
         End Sub, client 
         ) 


    Return (False) 
End Function 

'Cross-thread safe code using InvokeRequired Pattern 
Private Sub SetIndicators(ByVal ok As Boolean) 

    If Me.Label1.InvokeRequired Then 
     Dim d As New Action(Of Boolean)(AddressOf SetIndicators) 
     Me.Invoke(d, ok) 
    Else 
     If ok = True Then 
      Label1.Text = "Online!" 
      Label1.ForeColor = Color.LimeGreen 
     Else 
      Label1.Text = "Offline!" 
      Label1.ForeColor = Color.DarkRed 
     End If 
    End If 
End Sub 

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click 
    Try 
     ' If My.Computer.Network.Ping("192.168.1.1") Then 

      ' Label1.Text = "Online!" 
      ' Label1.ForeColor = Color.LimeGreen 

     ' Else 
      ' Label1.Text = "Offline!" 
      ' Label1.ForeColor = Color.DarkRed 
     ' End If 
     SetIndicators(My.Computer.Network.Ping("stackoverflow.com")) 
    Catch ex As Exception 
     'error occured 
     MessageBox.Show(ex.Message) 

    End Try 

End Sub 

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click 
    'result can be returned late according connection timeout 
    checkport("stackoverflow.com", 450) 
End Sub 

Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click 
    'should return online cause http port accessible 
    checkport("stackoverflow.com", 80) 
End Sub