I cant telnet on Mandriva Linux 2006. I am new to Linux but I suppose when you telnet you type the command telnet something.com port number

But when I type telnet it says command not found. What do I do?

Install the telnet package using your favourite package management tool. Here are two links with more info to help you out:

http://club.mandriva.com/xwiki/bin/Downloads/
http://www.marcelgagne.com/urpmi_install.html

But on your distribution, basically, logued in as root:

Telnet server is dead. Period. Don't use it. SSH is the successor.

Agreed. Don't install telnet. You can, and should, remote access from the command line using SSH. Telnet will get you hacked in minutes of it going on line.

What if you don't own the remote machine and that it uses telnet only (this is not often the case but it still happens....) ? What if you want to use telnet to connect to a machine on a telnet like service (smtp, pop) on a different port ?

Well don't install a telnet server should be the more correct answer. If you have to use telnet to access a remote machine I would look to try and change that if all possible. Telnet for email access is ok as all email is transmited in the clear anyway. One reason you need to use PGP....

On Mandriva the telnet client comes in the telnet package and the telnet server comes in the telnet-server package. Your box will be safe if you just install the telnet package (it comes installed by default - you must not have selected one of the package groups during install) although be aware that the username/password and all the commands and data you send to the remote box will be sent in the clear.

Only use it if you really have to.

Can you provide just ONE example? Just one IP addrss or server name that offers telnet login to it's users? Telnet server was dead when first cracker entered computing world and buried into an unmarked place when first commercial cracker came around.

The company I work for writes Network Management software that is sold to some of the biggest corporations in in the world, ie. corps with 10's of thousands of servers. Their networks consist to a large part of legacy Unix servers which still use rlogin or telnet, not to mention all the switches and routers which use it. We've even had requests to install the telnet-server on our scanning machines since their network firewalls/routers are all setup to allow telnet through for the sysadmins, but not ssh.

So in answer to your question I could give you thousands of examples just from the companys that we deal with. I'm sure they don't allow telnet access from the public internet, but still at many large companies their internal networks have significant parts that are still on telnet or rlogin.

In an ideal world, yes, but legacy software hangs around for a long, long time. Corect me if I'm wrong but even new Cisco routers still come with telnet on by default, you have to manually turn it off and enable ssh.

Well, I'm not here to argue about things like that. Obviously there are some obsolete solutions floating around. Which does not mean one should set up something new and fresh based on a telnet server.

Agreed and I'm not trying to start an argument either. I was just pointing out that telnet is still used a lot as a remote login method around the place, its far from dead (unfortunately ).

192.168.3.34 - 192.168.1.56 - etc.... remote access to old sun hardware console that do not have an ssh option, old routers/switch that do not have ssh options nor web interfaces, old hardware running an out of age linux (and still needed for some historical reason), etc.... and that are still in use at some client places... althought I need to remotly login throuh ssh on a local box (or physically connect to the local network) before I can reach them, I then need a telnet client to operate on them. These situations are rather rare but still happen.