difference between telnet and ssh

[sharp learner]

Hello
I am studying the Operating system (linux) for the first time.
I was asked to make free shell account with telnet facility.
I made the one ,but it says that server is not providing telnet but SSH.
I want to know the difference between the two?
what's their purpose and is SSH can be used as substitute for telnet?

If anyone know free shell account's URL please let me know.

thanks

[sicarie]

Hello
I am studying the Operating system (linux) for the first time.
I was asked to make free shell account with telnet facility.
I made the one ,but it says that server is not providing telnet but SSH.
I want to know the difference between the two?
what's their purpose and is SSH can be used as substitute for telnet?

If anyone know free shell account's URL please let me know.

thanks

Wikipedia has good articles on both, I believe you'll find those questions pretty easy to answer after reading these:

http://en.wikipedia.org/wiki/Telnet
http://en.wikipedia.org/wiki/Ssh

And a good ssh client (for Windows) is putty.