TraceRoute and Ping in C#

Given that I had to write a TraceRoute class today I figured I might as well share the source code.

using System.Collections.Generic;
using System.Net.NetworkInformation;
using System.Text;
using System.Net;

namespace Answer
{  
  public class TraceRoute
  {
    private const string Data = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";

    public static IEnumerable<IPAddress> GetTraceRoute(string hostNameOrAddress)
    {
      return GetTraceRoute(hostNameOrAddress, 1);
    }
    private static IEnumerable<IPAddress> GetTraceRoute(string hostNameOrAddress, int ttl)
    {
      Ping pinger = new Ping();
      PingOptions pingerOptions = new PingOptions(ttl, true);
      int timeout = 10000;
      byte[] buffer = Encoding.ASCII.GetBytes(Data);
      PingReply reply = default(PingReply);

      reply = pinger.Send(hostNameOrAddress, timeout, buffer, pingerOptions);

      List<IPAddress> result = new List<IPAddress>();
      if (reply.Status == IPStatus.Success)
      {
        result.Add(reply.Address);
      }
      else if (reply.Status == IPStatus.TtlExpired || reply.Status == IPStatus.TimedOut)
      {
        //add the currently returned address if an address was found with this TTL
        if (reply.Status == IPStatus.TtlExpired) result.Add(reply.Address);
        //recurse to get the next address...
        IEnumerable<IPAddress> tempResult = default(IEnumerable<IPAddress>);
        tempResult = GetTraceRoute(hostNameOrAddress, ttl + 1);
        result.AddRange(tempResult);
      }
      else
      {
        //failure 
      }

      return result;
    }
  }
}

And a VB version for anyone that wants/needs it

Public Class TraceRoute
    Private Const Data As String = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"

    Public Shared Function GetTraceRoute(ByVal hostNameOrAddress As String) As IEnumerable(Of IPAddress)
        Return GetTraceRoute(hostNameOrAddress, 1)
    End Function
    Private Shared Function GetTraceRoute(ByVal hostNameOrAddress As String, ByVal ttl As Integer) As IEnumerable(Of IPAddress)
        Dim pinger As Ping = New Ping
        Dim pingerOptions As PingOptions = New PingOptions(ttl, True)
        Dim timeout As Integer = 10000
        Dim buffer() As Byte = Encoding.ASCII.GetBytes(Data)
        Dim reply As PingReply

        reply = pinger.Send(hostNameOrAddress, timeout, buffer, pingerOptions)

        Dim result As List(Of IPAddress) = New List(Of IPAddress)
        If reply.Status = IPStatus.Success Then
            result.Add(reply.Address)
        ElseIf reply.Status = IPStatus.TtlExpired Then
            'add the currently returned address
            result.Add(reply.Address)
            'recurse to get the next address...
            Dim tempResult As IEnumerable(Of IPAddress)
            tempResult = GetTraceRoute(hostNameOrAddress, ttl + 1)
            result.AddRange(tempResult)
        Else
            'failure 
        End If

        Return result
    End Function
End Class

What follows is a significantly better C# implementation of tracert than exists in other answers thus far.

public static IEnumerable<IPAddress> GetTraceRoute(string hostname)
{
    // following are similar to the defaults in the "traceroute" unix command.
    const int timeout = 10000;
    const int maxTTL = 30;
    const int bufferSize = 32;

    byte[] buffer = new byte[bufferSize];
    new Random().NextBytes(buffer);

    using (var pinger = new Ping())
    {
        for (int ttl = 1; ttl <= maxTTL; ttl++)
        {
            PingOptions options = new PingOptions(ttl, true);
            PingReply reply = pinger.Send(hostname, timeout, buffer, options);

            // we've found a route at this ttl
            if (reply.Status == IPStatus.Success || reply.Status == IPStatus.TtlExpired)
                yield return reply.Address;

            // if we reach a status other than expired or timed out, we're done searching or there has been an error
            if (reply.Status != IPStatus.TtlExpired && reply.Status != IPStatus.TimedOut)
                break;
        }
    }
}

Pitfalls fixed here that are present in other answers include:

• It's lazy. Ex: it properly uses enumerable / an iterator so don't have to compute the entire tree, you can stop at any point by breaking out of your own consuming loop.
• maxTTL implemented so the function doesnt spin on forever.
• bufferSize option which is consistent with other tracert implementations.
• It's super concise and clean. It's contained in a single method and is considerably shorter than other options here.

Although the Base Class Library includes Ping, the BCL does not include any tracert functionality.

However, a quick search reveals two open-source attempts, the first in C# the second in C++:

• http://www.codeproject.com/KB/IP/tracert.aspx
• http://www.codeguru.com/Cpp/I-N/network/basicnetworkoperations/article.php/c5457/