Thursday, March 30, 2006

I always swore that when I got to the top of the Cisco Certification mountain, I'd never turn into one of those guys who act like they know everything and were born that way. Part of that promise to myself included remembering what it's like to see a technology for the first time, or to wonder "why would anyone use that?"

I definitely remember thinking that the first time I learned about Trivial File Transfer Protocol, or TFTP. Sure, I memorized the port number in my Intro studies (as you probably did), but I didn't really understand why anyone would use it. Why would you ever use TFTP instead of FTP? As someone once said to me, "When I transfer files, there's nothing trivial about it!"

Of course, the major drawback of TFTP is that is has no security features, and this includes a lack of password capabilities. Those of you who know your ISDN and have ever read one of my tutorials on that subject know that I warn you again using Password Authentication Protocol (PAP), since PAP sends a clear-text password across an ISDN link. So if I warn you again using PAP in the real world, why would I tell you to know TFTP?

TFTP is used in the Cisco world to perform IOS upgrades and to save configs to a TFTP Server. Cisco routers can themselves serve as TFTP servers, or you can use a workstation to fill that role.

If you needed to copy an IOS image to a router, for example, you could do so easily by connecting your PC to the router’s console port (via a rollover cable, right?). Your PC would need to run TFTP server software. There are quite a few free TFTP server software programs that work quite well – just enter “free tftp server” into Google or your favorite search engine and you’ll see what I mean.

Using TFTP in this fashion is a great way to have backup copies of IOS images or router configs right on your laptop. And take it from me, when the day comes that you need those backups, you’ll be glad you did!

The copy command tends to be a little confusing when you first start using it. Remember that when using the copy command, you first indicate where you’re copying from, then where you’re copying to:

R1#copy flash tftp
Source filename []? Example
Address or name of remote host []?

When performing such a copy, you’ll need to name the file you’re copying, as well as the IP address of the device you’re copying to. Since we're dealing with IOS filenames, these filenames can be a little long, so be careful when entering the filenames.

Using TFTP to perform IOS upgrades takes a little getting used to, especially the syntax of the copy command. But knowing that syntax and how to use TFTP will indeed get you one step closer to the CCNA!

To your Cisco success,

Chris Bryant
CCIE #12933

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