Getting Started with SSH/Telnet
You’re
probably already familiar with the process
of making a dial-up PPP connection to the Internet from your Windows
PC or Macintosh. Once connected, you then run client software to
access various Internet services: a web client
(like Netscape Navigator) to access web sites, a mail
client (like Netscape’s mail reader, or Eudora) to
send and receive email, or an FTP client (like
WS_FTP or Fetch) to transfer files. Traditionally, a Telnet
client is just another piece of software that runs on top
of your Internet connection. You use Telnet to log into a
shell session
on a remote server. Once you’re
in the shell session, you type text commands into the Telnet window,
and those commands are then executed on the remote server and the
results sent back to you.
We’ll talk more about shell sessions. For now, let’s talk a bit more about Telnet.
There’s an inherent problem with using Telnet to connect to a
remote server. Because Telnet traffic is sent across the network
unencrypted, a malicious user located on a network somewhere along
the path between you and the web server could easily obtain your
username and password and use them to connect to the server as you.
For that reason, a growing number of ISPs don’t allow customers
to make Telnet connections to their servers. Instead, they require
customers to use something called ssh (for
secure shell), an encrypted protocol that makes it much harder for bad guys to get hold of your login information. Once ...