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Configuring RIPv2 and EIGRP authentication with key chains can be tricky at first, and the syntax isn’t exactly easy to remember. But for BSCI and CCNP exam success, we’ve got to be able to perform this task.

In a previous tutorial, we saw how to configure RIPv2 packet authentication, with both clear-text and MD5 authentication schemes. EIGRP authentication is much the same, and has the text and MD5 authentication options as well. But EIGRP being EIGRP, the command just has to be a little more detailed!

As with RIPv2, the authentication mode must be agreed upon by the EIGRP neighbors. If one router’s interface is configured for MD5 authentication and the remote router’s interface is configured for text authentication, the adjacency will fail even if the two interfaces in question are configured to use the same password.

We’ll now configure link authentication on the adjacency over an Ethernet segment. Below, you’ll see how to configure a key chain called EIGRP on both routers, use key number 1, and use the key-string BSCI. Run show key chain on a router to see all key chains.

R2(config)#key chain EIGRP

R2(config-keychain)#key 1

R2(config-keychain-key)#key-string BSCI

R2#show key chain

Key-chain EIGRP:

key 1 — text “BSCI”

accept lifetime (always valid) - (always valid) [valid now]

send lifetime (always valid) - (always valid) [valid now]

R3(config)#key chain EIGRP

R3(config-keychain)#key 1

R3(config-keychain-key)#key-string BSCI

R3#show key chain

Key-chain EIGRP:

key 1 — text “BSCI”

accept lifetime (always valid) - (always valid) [valid now]

send lifetime (always valid) - (always valid) [valid now]

The EIGRP command to apply the key chain is a bit of a pain to remember, because the protocol and AS number is identified in the middle of the command, not the beginning. Also note that two commands are needed - one to name the key chain, another to define the authentication mode in use.

R2(config)#interface ethernet0

R2(config-if)#ip authentication key-chain eigrp 100 EIGRP

R2(config-if)#ip authentication mode eigrp 100 md5

5d07h: %DUAL-5-NBRCHANGE: IP-EIGRP 100: Neighbor 172.12.23.3 (Ethernet0) is down: keychain changed

R3(config)#interface ethernet0

R3(config-if)#ip authentication key-chain eigrp 100 EIGRP

R3(config-if)#ip authentication mode eigrp 100 md5

5d07h: %DUAL-5-NBRCHANGE: IP-EIGRP 100: Neighbor 172.12.23.2 (Ethernet0) is up:

As with RIPv2, the existing adjacency was torn down when one side was configured with authentication. If the key chain is correctly defined and applied on both sides, the adjacency will come back up. Always run show ip eigrp neighbor to make sure the adjacency is present. Learn the details of EIGRP key chains by configuring them on your home lab equipment, and you’ll be more than ready for BSCI exam success!

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage, home of free CCNP and CCNA tutorials, The Ultimate CCNA Study Package, and Ultimate CCNP Study Packages.

For a FREE copy of his latest e-books, “How To Pass The CCNA” and “How To Pass The CCNP”, just visit the website! You can also get FREE CCNA and CCNP exam questions every day! Pass the CCNP exam with The Bryant Advantage!

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Flash drives (a.k.a memory sticks, usb drives, usb keys and thumb drives) make it increasingly easy to take your data on the road. With gigabytes of storage available, you can take all of your spreadsheet, presentation and document files wherever you go.

Unfortunately, your data isn’t any good if you don’t also have the appropriate applications. Public computers at libraries, internet cafes and hotel lobbies often have only a browser installed. Business offices will have a full suite of applications, but not everyone uses Microsoft Office. And even if they do, the applications may be locked behind password protected security systems.

Using another person’s computer also presents a security risk. Any time you use an application, you leave behind traces of your visit. Productivity software often will store older versions of files as a courtesy to the user. That courtesy can become a real threat if you have proprietary information.

The good news is that, as the capacity of flash drives continues to increase, it has become increasingly easy to take simply take your applications with you. And in doing so, you dramatically reduce your security exposure.

Running software from your flash drive, however, is not as simple as installing Office to the stick instead of to your hard drive. Flash drive portable applications need to be able to run entirely off the drive, without installing anything on the host computer. They can’t rely on the host having Visual Basic, .Net or Java. They can’t be location dependent, because when you plug your drive into a host, you can’t control what drive letter your device will be assigned. And settings and files also need to be stored on your portable drive, not on the host.

Fortunately, there are an increasing number of applications that meet these requirements. Even better: the best of these are FREE.

Portable Open Office

Open Office is the amazing, free, Microsoft Office compatible suite that includes a word processor, spreadsheet, presentation tool, drawing package and database. While some of the interface is a little different, for the most part, if you know how to use MS Office, you know how to use Open Office.

While Open Office was designed to run on desktop machines, there’s also a “portable” version that runs off your flash drive. The applications take up 144MB installed, so you’ll need a bigger drive, but these days, that’s no problem.

Portable Firefox

Firefox is another desktop application that has made its way to the portable world. Whiles any computer you use will have a browser, Portable Firefox will make your life easier in several ways:

First, it allows you to import your bookmarks from your desktop version. So when you are on the road, you are never at a loss for the url of that important site. Second, it lets you use all of the plugins that you have become accustomed to. And finally, it won’t leave any traces of your web surfing on the host. No one will be able to see your “history”, or a cache of the sites you visited.

Photofiltre

If you need any proof that big things can come in small packages, you jut need to take a look at Photofiltre. Its a full featured painting / photo editing package that fits on, and runs from, a flash drive.

Foxit Reader

The Portable Document Format (pdf) file has become the defacto format for transfering documents between users while retaining formatting. Foxit Reader is a small, fast pdf reader for your flash drive.

PStart

To manage the applications on your flash drive, PStart is then ideal launcher. Because it uses relative paths to launch the applications, PStart doesn’t get confused when the drive gets assigned different letters on different computers. To add applications to the main menu list, you just right click. PSmaart also offers search and not taking functions.

Links to all of the programs discussed above can be found at The Flash Drive Blog.

John Retzer has worked as a professional journalist, photographer, editor, public relations professional and golf coach. He currently teaches economics, political science and history. In his “spare time” he runs several websites and blogs, including The Flash Drive Blog at http://www.flashdriveblog.com and Golf Blogger at http://www.golfblogger.com.

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