Ccna routing and Switching Complete Study Guide

Trivial File Transfer Protocol (TFTP)

Trivial File Transfer Protocol (TFTP) is the stripped-down, stock version of FTP, but it’s 

the protocol of choice if you know exactly what you want and where to find it because it’s 

fast and so easy to use!

f I g u r e   3 . 4     Secure Shell

>ssh admin@1.1.1.2

Can I have access to

your command line?

I accept only

encrypted data!

Here is my encrypted

username, password and

key: a@#$alskdjf2H!Vm34

Here is my response:

eSgkh2g42#$!@!#!$kjka12s

f I g u r e   3 . 5    FTP

>ftp@1.1.1.2

I want to get a file!

Which one?

I don’t know, what do

you have available?

No problem! Here is my

directory of available files!

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Chapter 3 

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  Introduction to TCP/IP 

But TFTP doesn’t offer the abundance of functions that FTP does because it has no 

directory-browsing abilities, meaning that it can only send and receive files (Figure 3.6). 

Still, it’s heavily used for managing file systems on Cisco devices, as I’ll show you in 

Chapter 7, “Managing a Cisco Internetwork.”

f I g u r e   3 . 6    TFTP

tftp 10.1.1.2

I want to get a file!

I’m not smart enough to

know what that means!

What files do you

have?

I’m TFTP! I don’t

know!

Fine! Give me a specific file

from Flash memory. Here is

the name of the file...

I can do that!

This compact little protocol also skimps in the data department, sending much smaller 

blocks of data than FTP. Also, there’s no authentication as with FTP, so it’s even more inse-

cure, and few sites support it because of the inherent security risks.

when should You use fTP?

Let’s say everyone at your San Francisco office needs a 50 GB file emailed to them right 

away. What do you do? Many email servers would reject that email due to size limits (a lot 

of ISPs don’t allow files larger than 5 MB or 10 MB to be emailed), and even if there are no 

size limits on the server, it would still take a while to send this huge file. FTP to the rescue!

If you need to give someone a large file or you need to get a large file from someone, FTP 

is a nice choice. To use FTP, you would need to set up an FTP server on the Internet so 

that the files can be shared.

Besides resolving size issues, FTP is faster than email. In addition, because it uses TCP 

and is connection-oriented, if the session dies, FTP can sometimes start up where it left 

off. Try that with your email client!

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TCP/IP and the DoD Model