Question

我有SNMP类创建SNMP数据包，然后创建一个UDP套接字来发送数据包..但是当我使用这个类发送Get Packet时，我没有得到任何响应......我已经到了这一点因为我使用wireshark来检查某些流量是否来自udp端口161，但我在调试程序时没有获得任何流量....这是创建套接字的类的一部分：

 Dim sock As New Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp)

        sock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 4500)

        ' Dim ihe As IPHostEntry = Dns.GetHostEntry(host)

        Dim iep As New IPEndPoint(IPAddress.Parse(host), 161)

        Dim ep As EndPoint = DirectCast(iep, EndPoint)

        sock.SendTo(packet, snmplen, SocketFlags.None, iep)

        udp1.Send(packet, packet.Length, iep)

        'Receive response from packet

        Try

            Dim recv As Integer = sock.ReceiveFrom(packet, ep)

        Catch generatedExceptionName As SocketException

            packet(0) = &HFF

            End Try

            Return packet

这是我用来发送SNMP get packet

的代码

Imports System.Text

Class Form1

    Dim commlength As Integer, miblength As Integer, datatype As Integer, datalength As Integer, datastart As Integer

    Dim uptime As Integer = 0

    Dim output As String

    Dim conn As New SNMP()

    Dim response As Byte() = New Byte(1023) {}

    ' Public Shared Sub Main(ByVal argv As String())

    'End Sub



    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        IPaddress.Text = "115.186.118.188"

        Community.Text = "public"



    End Sub



    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click



        ListBox1.Items.Add("Device SNMP information:")



        ' Send sysName SNMP request

        response = conn.[get]("get", IPaddress.Text, Community.Text, "1.3.6.1.2.1.1.5.0")

        If response(0) = &HFF Then

            ListBox1.Items.Add("No response from " & IPaddress.Text)

            Return

        End If



        ' If response, get the community name and MIB lengths

        commlength = Convert.ToInt16(response(6))

        miblength = Convert.ToInt16(response(23 + commlength))



        ' Extract the MIB data from the SNMP response

        datatype = Convert.ToInt16(response(24 + commlength + miblength))

        datalength = Convert.ToInt16(response(25 + commlength + miblength))

        datastart = 26 + commlength + miblength

        output = Encoding.ASCII.GetString(response, datastart, datalength)

        ListBox1.Items.Add("  sysName - Datatype:" & datatype & "," & output)

End Class

SNMP数据包未到达目标

0 个答案: