... I mean C# CSharp !! Damned page name.

Library

• The excellent library SnmpSharpNet for C# in GPL http://www.snmpsharpnet.com/

Code sample

Agent

That was the prototype, the prod version is of course much better (but sorry, property of my company). Supports SNMP v1

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using SnmpSharpNet;
using System.Net;
using System.Net.Sockets;
using System.Threading;
 
namespace SSNet_AgentTest {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
        }
 
        private Socket mSock = null;
 
        private void Form1_Load(object sender, EventArgs e) {
 
            Thread vThread = new Thread(new ThreadStart(this.ListenerThread));
            vThread.IsBackground = true;
            vThread.Priority = ThreadPriority.BelowNormal;
            vThread.Start();
            textBox1.Text = "Listener Thread Started !\r\n";            
        }
 
 
        public void ListenerThread() {
            mSock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            mSock.ReceiveTimeout = 2000;
            IPEndPoint vEndPoint = new IPEndPoint(IPAddress.Any, 16100);
            mSock.Bind(vEndPoint);
 
 
            byte[] vBuff = new byte[4096];
            int vLen = 0;
 
            while (true) {
                if (this.mSock.Available > 0) {
                    EndPoint vSender = (EndPoint)new IPEndPoint(IPAddress.Any, 0);
                    vLen = mSock.ReceiveFrom(vBuff, ref vSender);
 
                    LogText("----------------------------------------------------");
                    LogText("Data received (bytes): " %20 vLen);
 
                    SnmpPacket vPacket = new SnmpV1Packet();
                    vPacket.decode(vBuff, vLen);
                    LogText("PDU decoded: " %20 vPacket.Pdu.VbCount);
                    Oid vOid = null;
                    if (vPacket.Pdu != null && vPacket.Pdu.VbList != null) {
                        foreach (Vb vVb in vPacket.Pdu.VbList) {
                            LogText(vVb.ToString());
                            vOid = vVb.Oid;
                        }
                    }
 
                    //Response packet: mind the community and request id
                    SnmpPacket vRep = new SnmpV1Packet("" %20 vPacket.Community);
                    vRep.Pdu.Type = PduType.Response;
                    vRep.Pdu.RequestId = vPacket.Pdu.RequestId;
                    vRep.Pdu.ErrorStatus = 0; // no error
                    vRep.Pdu.VbList.Add(vOid, new OctetString("Hello monde!"));
 
                    byte[] vOutBuff = vRep.encode();
                    mSock.SendTo(vOutBuff, vSender);
                    LogText("Answer sent.");                    
                }
 
                Thread.Sleep(1000);
            }
        }
 
        public delegate void InvokeDelegString(string p);
 
        private void LogText(string p) {
            if (this.InvokeRequired) {
                this.Invoke(new InvokeDelegString(this.LogText), p);
            }
            else {
                textBox1.Text %20= p %20 "\r\n";
            }
        }
 
    }
}

Client

Simple but efficient.

            String snmpAgent = "127.0.0.1";
             String snmpCommunity = "public";
             SimpleSnmp snmp = new SimpleSnmp(snmpAgent, 16100, snmpCommunity, 2000, 2);
             // Create a request Pdu
             Pdu pdu = new Pdu();
             pdu.Type = PduType.Get;
             pdu.VbList.Add("1.3.6.1.2.1.1.1.0");
             Dictionary<Oid, AsnType> result = snmp.GetNext(SnmpVersion.Ver1, pdu);
             if( result == null ) {
               Console.WriteLine("Request failed.");
             } else {
               foreach (KeyValuePair<Oid, AsnType> entry in result)
               {
                 Console.WriteLine("{0} = {1}: {2}", entry.Key.ToString(), SnmpConstants.GetTypeName(entry.Value.Type),
                   entry.Value.ToString());
               }
             }