C # Telnet Library

Question

Is there a good, free telnet library available for C # (not ASP.NET)? I found several on google, but everyone has one problem (do not support login / password, do not support script).

I assume that MS still did not include the telnet library as part of .NET v3.5, as I could not find it if it were. I would loooooove to be wrong though.

Answer 1

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

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

Answer 2

Here is my code that finally works

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"); } } 

Answer 3

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

Answer 4

Here is the telnet library and program, which uses it as an example. The entire source (including the source of the library) is at the bottom of the article.

The example logs in to the Cisco router and loads the configuration.

http://www.xpresslearn.com/networking/code/csharp-telnet-client

Answer 5

I doubt very much that the telnet library will ever be part of .NET BCL, although you have almost full socket support, so it would be too difficult to emulate the telnet client, Telnet in its common implementation is a legacy and dying technology in which, like usually located behind a beautiful new modern facade. Regarding the Unix / Linux variants, you will find that from its SSH and the inclusion of telnet it is usually considered bad practice.

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

You will still need to create your own wrapper for handling events to enter input into scripts.

Answer 6

I ended the search for MinimalistTelnet and adapted it for my purposes. In the end, I had to change the code a lot because of the unique ** device I'm trying to connect to.

** Unique in this case can be correctly interpreted as a "dead brain".

Answer 7

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

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

Hope this helps.

Regards, Andy.

Answer 8

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