ActiveXperts Network Component

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Visual Basic .NET SNMP Trap Receiver Sample Source Code

Network Component provides an easy-to-use development interface to a variety of IP protocols. By using Network Component, you can very easily create or enhance applications with network features.

Network Component features the following: DNS, FTP, HTTP, HTTPs, ICMP Ping, IP-to-Country, MSN, NTP, RSH, SCP, SFTP, SNMP v1/v2c (Get, GetNext, Set), SNMP Traps, SNMP MIB, SSH, TCP, Telnet, TFTP, UDP, Telnet, Wake-On-LAN and more.

Network Component can be well integrated into any development platform that supports ActiveX objects.


Network Component is compliant with SNMP v1 and SNMP v2c. Several SNMP data types are supported, including:

  • String types (also called "octet strings");
  • Integer types (16bit, 32bit, 64bit and unsigned integers);
  • IP Address types;
  • Timetick types;
  • Counter types (32bit and 64bit counters);
  • OID types (also called "Object ID's");
  • Other, less frequently used datatypes.

Network Component SNMP traps features:

  • SNMP v1 and SNMP v2c support;
  • Support for aplphanumeric OID's (object identifier) and numeric OID's;
  • Multi-threading architecture: send SNMP traps simultaneously from one process using multiple threads;
  • Support for ports other than the default 161 and 162 ports;
  • Support for enterprise specific traps;
  • Support for SNMP v1 generic traps;
  • Send multiple variables in a single SNMP TRAP message.

Step 1: Download and install the Network Component

Download Network Component from the ActiveXperts Download Site and start the installation. The installation guides you through the installation process.

Step 2: Create a new Visual Basic .NET Project

Launch Microsoft Visual Studio (for instance 'Microsoft Visual Studio 2008') from the Start menu. Choose 'New' from the 'File' menu and click on 'Project'. In the 'New Project' dialog, select a Visual Studio template (for instance: 'Console Application'). Select a name for the application (for instance: 'DemoApp') and a name for the solution (for instance: 'DemoSolution'). Also, select the directory where you want to store the project (for instance: 'C:\MyProjects):

(Click on the picture to enlarge)

Step 3: Refer to the Network Component Library and create the objects

Now that a new project has been created, you must add a reference to the Network Component in the project to be able to use the the Network Component object. To do so, choose 'Add Reference...' from the 'Project' menu. In the 'Add Reference' dialog that pops up, select the 'COM' tab and select the 'Network Component 4.4 Type Library' as shown in the following picture:

(Click on the picture to enlarge)

Click 'OK' to close the 'Add Reference' dialog.

On top of your code, type the following line to use the Network Component namespace:

Imports AxNetwork

In your Main function, declare and create the following object:

Public m_objSnmpMib As SnmpMibBrowser
m_objSnmpMib = New SnmpMibBrowser ()

Appendix: Full source code

Imports System.IO
Imports AxNetwork

Module SnmpTrapProgram

    Sub Main()
        Dim objSnmpTrapManager As AxNetwork.SnmpTrapManager = New AxNetwork.SnmpTrapManager
        Dim objSnmpTrap As AxNetwork.SnmpTrap = New SnmpTrap
        Dim objConstants As AxNetwork.NwConstants = New AxNetwork.NwConstants
        Dim objSnmpObject As AxNetwork.SnmpObject = New AxNetwork.SnmpObject
        Dim strHostName As String = "", strCommunity As String = "", strMibFile As String = ""

        ' A license key is required to unlock this component after the trial period has expired.
        ' Call 'Activate' with a valid license key as its first parameter. Second parameter determines whether to save the license key permanently 
        ' to the registry (True, so you need to call Activate only once), or not to store the key permanently (False, so you need to call Activate
        ' every time the component is created). For details, see manual, chapter "Product Activation".
        '
        ' objSnmpTrapManager.Activate("XXXXX-XXXXX-XXXXX", False)

        ' Display component information
        Console.WriteLine("ActiveXperts Network Component {0}{1}Build: {2}{3}Module: {4}{5}License Status: {6}{7}License Key: {8}{9}", objSnmpTrapManager.Version, Environment.NewLine, objSnmpTrapManager.Build, Environment.NewLine, objSnmpTrapManager.Module, Environment.NewLine, objSnmpTrapManager.LicenseStatus, Environment.NewLine, objSnmpTrapManager.LicenseKey, Environment.NewLine)

        ' Set Logfile (optional, for debugging purposes)
        objSnmpTrapManager.LogFile = Path.GetTempPath() + "SnmpTrapManager.log"
        Console.WriteLine("Log file used: {0}{1}", objSnmpTrapManager.LogFile, Environment.NewLine)

        strHostName = ReadInput("Enter SNMP (remote) host (leave blank to use 'localhost'):", "localhost")
        strCommunity = ReadInput("Enter community (leave blank to use 'public'):", "public")
        strMibFile = ReadInput("Enter MIB file (optional):", "")
        Console.WriteLine("Agent: " + strHostName)
        Console.WriteLine("Community: " + strCommunity)
        Console.WriteLine("MIB file: " & strMibFile)

        ' To enable logging, assign a valid log file to the LogFile property
        ' objSnmpTrapManager.LogFile = "C:\SnmpManagerTrapDemo.log"

        ' Set protocol version
        objSnmpTrapManager.ProtocolVersion = objConstants.nwSNMP_VERSION_V2C

        ' SNMP Initialize
        objSnmpTrapManager.Initialize()
        Console.WriteLine("Initialize, result: " + objSnmpTrapManager.LastError.ToString() + " (" + objSnmpTrapManager.GetErrorDescription(objSnmpTrapManager.LastError) + ")")
        If (objSnmpTrapManager.LastError <> 0) Then

            System.Threading.Thread.Sleep(5000) ' Sleep for 5 seconds before exit		
            Exit Sub
        End If

        If (strMibFile <> "") Then
            objSnmpTrapManager.LoadMibFile(strMibFile)
        End If

        ' Set trap properties
        objSnmpTrap.Clear()
        objSnmpTrap.Host = strHostName
        objSnmpTrap.Community = strCommunity
        objSnmpTrap.Port = 162

        ' Add first variable to trap
        objSnmpObject.Clear()
        objSnmpObject.OID = ".1.3.6.1.2.1.1.5.0"
        objSnmpObject.Type = objConstants.nwSNMP_TYPE_IPADDRESS
        objSnmpObject.Value = "10.0.0.1"
        objSnmpTrap.AddObject(DirectCast(objSnmpObject, Object))

        ' Add second variable to trap
        objSnmpObject.Clear()
        objSnmpObject.OID = ".1.3.6.1.2.1.1.5.1"
        objSnmpObject.Type = objConstants.nwSNMP_TYPE_OCTETSTRING
        objSnmpObject.Value = "One two three"
        objSnmpTrap.AddObject(DirectCast(objSnmpObject, Object))

        ' Send the trap. If you want to use another port than default SNMP trap port 162, set it as optional 2nd parameter
        objSnmpTrapManager.Send(DirectCast(objSnmpTrap, Object))
        Console.WriteLine("Send, result: " & objSnmpTrapManager.LastError.ToString() & " (" & objSnmpTrapManager.GetErrorDescription(objSnmpTrapManager.LastError) & ")")

        ' Shutdown
        objSnmpTrapManager.Shutdown()
        Console.WriteLine("Shutdown, result: " & objSnmpTrapManager.LastError.ToString() & " (" & objSnmpTrapManager.GetErrorDescription(objSnmpTrapManager.LastError) & ")")

        Console.WriteLine("Ready.")
        System.Threading.Thread.Sleep(5000) ' Sleep for 5 seconds before exit		
    End Sub

    Private Function ReadInput(ByVal strTitle As String, ByVal strDefault As String) As String

        Dim strInput As String = ""

        Console.WriteLine(strTitle)
        Console.Write("  > ")
        strInput = Console.ReadLine()
        If (strInput = "") Then
            strInput = strDefault
        End If

        ReadInput = strInput
    End Function

End Module

You can download the complete sample on our FTP site ftp.activexperts-labs.com/samples/network-component/. There are many other working Network Component scripts on our site and shipped with the product.

NOTE: Demo Projects are created with Microsoft Visual Studio 2008

The Network Component project ships with a set of Microsoft Visual Studio .NET samples, including samples for Microsoft Visual C# .NET. The projects are created with Microsoft Visual Studio 2008.

Users with a later version of Microsoft Visual Studio can open such a project. The Visual Studio Conversion Wizard will guide you through the process of converting the project to the version used.