SSH en FTP

[Bernouilli]

Hello

I'm a little confused about ssh en ftp.
In the beginning when is was reading about ssh, I though it was just like
telnet but a safer way. In other words giving remote commands, but you can not
transfer files from client A to client B with it right? You can only move files and other
stuff on the computer where you are logged in through ssh.

Now here comes the point when i'm confused, sometimes I read when your ssh connection is
established, it's safer to use ftp. This i don't understand.

If you have a ssh connection to client B( for executing remote commands) and a ftp connection to client B (for file tranfer). The ftp data is still plain text right?

Also the difference between SSL and SSH I don't really understand. SSL makes a safe connection from A to B, and then you can safely communicate with each other for any purpose. SSH is just a safe connection from A to B, to execute commands on B right?

I don't really see the trees through the forest anymore

thanks!

[dxqcanada]

FTP is unsecure.

OpenSSH includes SFTP and SCP for file transfers.
SSH creates a channel for running a shell on a remote computer, with end-toend encryption between the two systems.

SSL provides authentication and encryption for TCP layer connections (Secure Socket Layer). Primary use is HTTPS.

[Freston]

It may help to expand the acronyms.

FTP="File Transfer Protocol"
It means just that, it's a protocol for transferring files. It's main benefit is that you may or may not need a valid login depending on server settings. It's used on the internet for example to allow anonymous downloads of Free and Open Source Software

SSH="Secure SHell"
And it means you have a secure shell on another machine. This is opposed to Telnet, where you have an unsecure shell on another machine. Both Telnet and SSH need you to have a valid login on the remote machine.
Secure and unsecure have their canonical meaning here, namely are they interceptable and thus exploitable. In effect, it all has to do with encryption. Really, the 'S' means encryption.
SSH is the default way to log in to a remote machine. Don't bother with Telnet unless you're dealing with legacy hard- or software.

SCP="Secure CoPy"
It's nothing but copy (cp), but then secure between machines. Contrary to FTP you need to be able to authenticate yourself on the remote machine (ie, you have a valid login and enough privilege over the intended file).
Note however that it is very confusing that it's syntax differs slightly from SSH.

(examples)
ssh -p <port number> remotemachine
scp -P <portnumber> localfile remotemachine

...and such


SSL="Secure Socket Layer"
Without going too much into detail here, cuz it's quite complicated, it's a secure connection between machines. It's used, as dxqcanada pointed out, for HTTPS, amongst other things.