Cisco Certification: Introduction To Isdn, Part Iii
|
Configuring PPP PAP Authentication
Now we know how the ISDN link comes up (interesting traffic), and some scenarios that might cause the link to stay up, we need to look at ISDN authentication schemes. The two methods Cisco certification candidates must be familiar with are PAP and CHAP.
Password Authentication Protocol (PAP) sends the username and password over the ISDN link in clear-text. Sending any passwords over any WAN link in clear-text is generally a bad idea, but itâ??s important to know you have this option.
Regarding both PAP and CHAP, itâ??s a common misunderstanding that each side must authenticate the other. PAP and CHAP both support bidirectional and unidirectional authentication that is, R1 can authenticate R2 without R2 necessarily authenticating R1. Itâ??s more common to use unidirectional authentication in a lab environment than a production network, but keep in mind that bidirectional authentication is an option, not a requirement.
The configurations of PAP and CHAP do have their similarities. For both, youâ??ll configure a username/password combination in global configuration mode. Newcomers to ISDN sometimes put the local router name in for the username remember that the remote router name is the username.
The only real advantage of PAP over CHAP comes in the password configuration. Since PAP actually sends the password as a whole over the link, the two routers can send different passwords during authentication. The operation of CHAP requires that both routers use the same password, and weâ??ll see why in tomorrowâ??s article.
Under the BRI interface, youâ??ll enter encapsulation ppp and ppp authentication pap. So far, your authentication scheme looks like this:
username R2 password CCNA
Int bri0
encapsulation ppp
ppp authentication pap
PAP requires an extra command at this point. The ppp pap sent-username command is required under the interface, indicating the username and password this router will be sending to the remote router.
Int bri0
encapsulation ppp
ppp authentication pap
ppp pap sent-username R1 password CISCO
I always encourage CCNA and CCNP candidates to use as many debugs as possible when working in their lab, since these commands show us how things work. For any PPP authentication, always run debug ppp negotiation before sending interesting traffic to trigger the call. Watching exactly how PAP and CHAP work give you a much better understanding of whatâ??s going on â??behind the commandâ??, and makes you a stronger candidate and a stronger networking engineer.
Tomorrow, weâ??ll take a look at CHAP, and why routers cannot use the same password on both ends of the link.
Keep studying!
About The Author:
Chris Bryant, CCIE (TM) #12933, has been active in the Cisco certification community for years. He worked his way up from the CCNA to the CCIE, and knows what CCNA and CCNP candidates need to know to be effective on the job and in the exam room.
He is the owner of http://www.thebryantadvantage.com, where he teaches CCNA and CCNP courses to small groups of exam candidates, ensuring they each receive the individual attention they deserve. Classes are offered over the Internet and in person in select cities. Chris has custom-written the Study Guide and Lab Workbook used in each course - no third-party training materials or simulators are used. You're invited to visit our site and check out our CCNA and CCNP Courses, Flash Card Books, and to sign up for our weekly newsletter written personally by Chris. Chris is always glad to hear from Cisco certification candidates at chris@thebryantadvantage.com.
|
|
|
Microsoft Crm In Latin America: Implementation, Customization, Support ? Overview For Consultant
Microsoft Business Solutions CRM is present several years on the US software market plus it makes a...(related: Software)
Introduction To Isdn, Part Ii
In the previous ISDN article, we looked at how and why one router dials another using ISDN. Just as important is knowing what keeps the link up once it is dialed.Why? Because ISDN acts as a phone call between two routers, and itâ??s billed that way to your client. The two routers that are connected by this phone call may be located in different area codes, so now weâ??re talking about a long distance phone call.If your ISDN link does not have a reason to dis...(related: Software)
Interactive Mapping Brings Information To Life
What is Interactive Mapping?Interactive mapping is a visual display medium which allows graphing, mapping, and even conversion to PDF of any type of information. This technology is used by national government agencies, airlines, chambers of commerce, ski resorts, and count...(related: Software)
What Stands Behind The Software Description?
With thousands of web pages added to the Net every day, it's getting more and more frustrating both to submit the information to the attention of those, who are interested in it and to find the information one needs.The problem is even aggravat...(related: Software)
Free Software: How Not To Get More Than You Bargained For!
I completed an experiment recently. I wanted to find out exactly what software I could get free on the Internet. My main focus was for software to include utilities and useful home business applications.I completed various searches for free software and related keywords on the leading search engines.What I found were thousands of web sites, proclaiming for you to be able to download software for free. Or at least a "try before you buy" basis.What I found was stunning.It seems once I downloaded a few of these ...(related: Software)
Design A Web Album Using Adobe Photoshop- Part 2
So let's begin crunching down these 300 images using Adobe Photoshop from start to finish. When I say 'crunching', to some 300 images may seem like allot, but it's not. I have done jobs for clients that have 100,000 plus images. When you have that many images to produce there are other programs I use that are designed for this. We'll cover that another day.To this point we have ensured that our images are web ready, cropping, retouching, watermarking, etc. So let's get at it. I will assume that we are all using Adobe Photoshop...(related: Software)
Editing Your Photos Using Microsoft Picture It Publishing Platinum 2002 - A Great Dinosaur
I started using PIP (Picture It Publishing) Platinum 2002 right after I got it in a bundle with my HP Pavallion N5295 Notebook more than several moons ago!I don't want to be a rocket scientist to produce edited photos quickly and with quality results, again and again.I had a terrible time at first with the edited pictures. Once I saved them and re-opened them they were out of focus. I tried everything I could think of and then I realized what was wrong.Just before you save it, it gives you the option as to what t...(related: Software)
Corporate Erp: Standard Vs. Rich Functionality ? Microsoft Great Plains
Traditionally we were considering functionally rich systems, such as SAP, Oracle Financials, PeopleSoft, JDEdwards as the fit for large publicly traded corporation. There might be multiple opinions for the future corporate ERP/MRP systems. We would like to give you our prognosis: high-end systems will be losing market to generic granulated standard functionality systems. Customization will be in high demand ? but it will be appropriate to go for light of medium customization versus purchasing high-end functionality system. It is not a secret, that nowadays multiple companies from Fortune 500 list use midmarket solution, such as Microsoft Great Plains as their corporate ERP. In this small article we'll try to defend our position and give you...(related: Software)
Hear It In Digits
Music downloads are off the charts! We're listening to digital music in the digital era.The driving force behind the phenonmena is the technonolgy called MP3.This is the technology that has changed the music industry.MP3 is an acronym for Motion Pictures Expert Group Audio Layer III. MPEG is the standard for audio or video compression that makes any files smaller wit...(related: Software)
Introduction To Isdn, Part Ii
In the previous ISDN article, we looked at how and why one router dials another using ISDN. Just as important is knowing what keeps the link up once it is dialed.Why? Because ISDN acts as a phone call between two routers, and itâ??s billed that way to your client. The two routers that are connected by this phone call may be located in different area codes, so now weâ??re talking about a long distance phone call.If your ISDN link does not have a reason to dis...(related: Software)
Free Software For Newbies And Web Developers
Here is some free software tools to help you build your own websites and create web products.Learning new skills is not difficult. It just takes a bit of willingness to give it a go. You will feel great satisfaction knowing that you can do this stuff.<...(related: Software)
site-map - Copyright © 2008 | Contact Webmaster | All Rights Reserved. | Software