C# Telnet Library

Is there a good, free telnet library available for C# (not ASP .NET)? I have found a few on google, but they all have one issue or another (don't support login/password, don't support a scripted mode).

I am assuming that MS still has not included a telnet library as part of .NET v3.5 as I couldn't find it if it was. I would loooooove to be wrong though.

Best C# Telnet Lib I've found is called Minimalistic Telnet. Very easy to understand, use and modify. It works great for the Cisco routers I need to configure.

http://www.codeproject.com/KB/IP/MinimalisticTelnet.aspx

Here is my code that is finally working

using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text.RegularExpressions;
using System.Threading;

class TelnetTest
{

    static void Main(string[] args)
    {
        TelnetTest tt = new TelnetTest();

        tt.tcpClient = new TcpClient("myserver", 23);
        tt.ns = tt.tcpClient.GetStream();

        tt.connectHost("admin", "admin");
        tt.sendCommand();

        tt.tcpClient.Close();
    }

public void connectHost(string user, string passwd) {
    bool i = true;
    while (i)
    {
        Console.WriteLine("Connecting.....");
        Byte[] output = new Byte[1024];
        String responseoutput = String.Empty;
        Byte[] cmd = System.Text.Encoding.ASCII.GetBytes("\n");
        ns.Write(cmd, 0, cmd.Length);

        Thread.Sleep(1000);
        Int32 bytes = ns.Read(output, 0, output.Length);
        responseoutput = System.Text.Encoding.ASCII.GetString(output, 0, bytes);
        Console.WriteLine("Responseoutput: " + responseoutput);
        Regex objToMatch = new Regex("login:");
        if (objToMatch.IsMatch(responseoutput)) {
           cmd = System.Text.Encoding.ASCII.GetBytes(user + "\r");
           ns.Write(cmd, 0, cmd.Length);
        }

        Thread.Sleep(1000);
        bytes = ns.Read(output, 0, output.Length);
        responseoutput = System.Text.Encoding.ASCII.GetString(output, 0, bytes);
        Console.Write(responseoutput);
        objToMatch = new Regex("Password");
        if (objToMatch.IsMatch(responseoutput))
        {
            cmd = System.Text.Encoding.ASCII.GetBytes(passwd + "\r");
            ns.Write(cmd, 0, cmd.Length);
        }

        Thread.Sleep(1000);
        bytes = ns.Read(output, 0, output.Length);
        responseoutput = System.Text.Encoding.ASCII.GetString(output, 0, bytes);
        Console.Write("Responseoutput: " + responseoutput);

        objToMatch = new Regex("#");
        if (objToMatch.IsMatch(responseoutput))
        {
            i = false;
        }

    }

    Console.WriteLine("Just works");
}
}

Another one with a different concept: http://www.klausbasan.de/misc/telnet/index.html

I ended up finding MinimalistTelnet and adapted it to my uses. I ended up needing to be able to heavily modify the code due to the unique** device that I am attempting to attach to.

** Unique in this instance can be validly interpreted as brain-dead.

I am currently evaluating two .NET (v2.0) C# Telnet libraries that may be of interest:

• http://www.thoughtproject.com/Libraries/Telnet/
• http://dotnettelnet.sourceforge.net/

Hope this helps.

Regards, Andy.

Another one, it is an older project but shares the complete source code: http://telnetcsharp.codeplex.com/

I doubt very much a telnet library will ever be part of the .Net BCL, although you do have almost full socket support so it wouldnt be too hard to emulate a telnet client, Telnet in its general implementation is a legacy and dying technology that where exists generally sits behind a nice new modern facade. In terms of Unix/Linux variants you'll find that out the box its SSH and enabling telnet is generally considered poor practice.

You could check out: http://granados.sourceforge.net/ - SSH Library for .Net http://www.tamirgal.com/home/dev.aspx?Item=SharpSsh

You'll still need to put in place your own wrapper to handle events for feeding in input in a scripted manner.