OK, just to make it some clearer :-) for those who did not find it most
readable, sorry for being native french speaker.
FTP stands for File Transfer Protocol. A protocol is like a language, more
or less a set of rules that defines the way two ore more computers exchange
data using a network. On the Internet network, the standard language is
named tcp/ip, and it comes in many variants (ftp is one, there is also arp,
http -ah! heard this already-). these variants have all something in common,
and each of them has some nice features dedicated to their respective
purpose.
When you type in your browser's adress bar: ftp://ftp.microsoft.com, this
commands your browser to communicate with the Internet host named
ftp.microsoft.com, using the ftp language. If the host is running a ftp
server program, it will respond to your and send some data.
Applications like the one you certainly use to upload files to your server
(i use ws-ftp, but thare are tons of those utilities around) are performing
most ftp handling operations automatically, transparently (behin the scene
your computer gets a greeting, identifies itself and sends some login
information. All this using the ftp protocol so you don't have to know
and/or handle this, too) A sample login using ftp looks like this on my
windows2000 machine: (you can type 'ftp' within a DOS command prompt -for
***x users, nothing more than a console window- and then type "open
<hosttname>" as soon as the 'ftp>' prompt appears)
C:\>ftp
ftp> open ftp.microsoft.com
Connected to ftp.microsoft.com.
220 CPMSFTFTPA06 Microsoft FTP Service (Version 5.0).
User (ftp.microsoft.com:(none)): anonymous
331 Anonymous access allowed, send identity (e-mail name) as password.
Password:
230-This is FTP.MICROSOFT.COM Please see the dirmap.txt
230-file for more information.
230 Anonymous user logged in.
ftp>
But one important point for techies: ftp is the name of the profgram, and
ftp is also the name of the protocol that the ftp program uses for its only
purpose: transfering files over the net... this makes things confusing. For
some people (larry??) ftp is even a verb.
Now just some information to telnet. Some web servers are also telnet
servers, that accepts sessions from telnet clients (ie your machine). to
open a session, just enter at your command promt: "telnet <hostname>"
(without the quotes, for sure). the telnet application starts and displays
in a terminal window a greeting from the host you just called (some are
non-polite, and coldly just request your username and password. When I
communicate from my windows2000 workstation with my linux boxnamed XBox23,
the telnet window first displays following lines of text: (oh yes, ....
we're all talking about old fashioned text-based things called terminals, no
graphics here except...see below)
Welcome to SuSE Linux 7.0 (i386) - Kernel 2.2.16 (2).
Hello. Swiss time is currently 15:42:34, looks like you're not working
overtime
XBOX23 login:
and then I have to enter my used-id and my password. (you can try out these
things if you know the adress of a telnet server.) Once logged in, you can
type in your commands at the prompt and the server will answer your request,
this is then all executed on the remote machine, not on your's. Your telnet
window is just a terminal, a open window to things happening on the remote
host. you can type in 'perl -v' and perl gets started on the server which in
turn sends the version information that comes from perl to your telnet
window.
So you see, ftp and telnet are both about communication between hosts (or
nodes, or workstations, or servers, or whatever you can understand under
'machine connected to the internet'). In some way, both are very similar
even if they're sometimes 'hidden' behind a graphical user interface where
you just use your mouse and let the program handle the low-level techie data
handling stuff
Did I make it clearer os is it just a total mess now ? just tell me :-)
If it's a mess you should consider reading 'computer networks' from Andrew
S. Tanenbaum. This is THE book out there.
have a nice day.
jm
(8~
> >
> >
> > Hi Sally
> >
> > Telnet is a tcp/ip based terminal emulation program. You can open a
> session
> > on remote hosts and perform actions directly as would you sit in front
of
> > the machine working with a console window.
> > Ftp (file transfer protocol) is just one of the dozens of protocols that
> > exist in the tcp/ip protocol suite. The front-end applications that help
> to
> > transfer files using a GUI are often confused with the protocol itself,
> that
> > just defines how the data is transported on the network
> >
> > (:~
> > Jean-Marc
> >
> > ----- Original Message -----
> > From: "Sally" <[EMAIL PROTECTED]>
> > To: "perlcgi" <[EMAIL PROTECTED]>
> > Sent: Thursday, June 14, 2001 2:52 PM
> > Subject: Telnet
> >
> >
> > > I've seen lots of references to telnet, but I can't find an
explanation
> of
> > > what it actually is. Is it similar to FTP?
> > >
> > >
> >
> >
>
>
