Use telnet work out your dreams

Posted by: jobinmartin on: March 16, 2007

• In: computer tips | hacking | hacks | Useful info
• 3 Comments

I’ll bet you’ve occasionally heard the word “telnet” mentioned as you’ve surfed the net. And I’ll also bet that, like most people, you really don’t have any idea what this strangely named thing is for. Yet this little known thing is one of the more powerful tools available to a webmaster.

What is telnet? This is a way to attach directly to a web server to give it commands. Using Telnet you are not talking through a web browser, an email client, a newsgroup reader or even an FTP program. In fact, what you can do with Telnet is log into your account on your server (or your hosts server) and make it do things that before now you’ve only dreamed of.

What is telnet exactly?

Telnet is a protocol (a well defined way of communicating) which allows character oriented communications between a client (you) and a computer system (the machine hosting your web site). Telnet basically makes the computer believe that your computer is an ASCII (character  based) terminal.

Why is Telnet useful?

Using Telnet you log directly into the server and feed it commands. This usually applies to Unix-style systems, although in theory it works as well on Windows NT and Windows 2000 hosts (usually Telnet is disabled on those kinds of operating systems due to severe security risks).

How do you get Telnet?

There are two parts to Telnet. First, you need to contact your web host and find out if they support Telnet access to your account. If you pay for your hosting and they run a Unix-style box, then it’s very likely that you will be granted Telnet access.

Once your host has granted you access, you will need to get a Telnet client. Some operating systems (such as Windows 2000 Professional) come with one of these clients automatically. Otherwise, you can do a quick search on Zdnet or Download.com to find a good one.

What Telnet clients are available?

There are many dozens, if not hundreds, of Telnet clients available. Some of them include the following:

• Netterm (Windows)
• SecureCRT (Windows)
• SimpTerm (Windows)
• Tera Term (Windows)

Once you have Telnet access, what can you do?

If the box is a Unix machine, you can feed to Unix commands. These are useful for determining the environment, setting up timed jobs, and performing certain specific maintenance tasks.

What commands do you need to know?

Once you’ve logged into the server, you will need to know and execute operating system commands. In general, these will be Unix commands (although VAX and Alpha based web hosts are still around), although you may occasionally run into a Windows system with Telnet access (these will need DOS commands).

What can’t you do with Telnet?

Telnet is not a web server so does not have a clue about web pages. It is also not an email client (although you may be able to run an email program from the Telnet session), a newsgroup reader or an FTP program.

How did Telnet come about?

Okay, put on your way-back glasses for minute so we can go back in time. Back in the good old days of computers, everything was done on huge, high-prices machines called mainframes. To communicate with a mainframe you used something called a terminal. The main difference between a terminal and a modern PC is a terminal is very stupid.

Terminals only allow a small set of characters (about 127 different ones) to be typed and printed. There are no graphics of any kind, and everything was black and white (no colors). Just characters being typed and printed from left to right.

Telnet was developed around 1980 by Jan Postel to allow people to connect to one of these computer systems from a remote location. The Telnet software pretended it was one of the really dumb terminals. That’s all Telnet is – a way to get to a machine and log in as if one were typing on a terminal.

Why don’t all web hosts support Telnet?

Supporting Telnet is more difficult than just running a standard web host. There are also significant security risks associated with this protocol which need to be considered.

Is there a free host which supports Telnet access?

It’s very unlikely that you will find a free host which allows Telnet access.

What is the future of Telnet?

Unix-style servers are very, very popular. Over time, I think, as better and better tools are developed I think Telnet will fade into the past. Until then, it’s sometimes the old way to get done what you need to get done.

 

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