Introduction To ISDN, Part III: PAP

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 it's important to know you have this option.

Regarding both PAP and CHAP, it'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. It'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, you'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 we'll see why in tomorrow's article.

Under the BRI interface, you'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 what's going on "behind the command", and makes you a stronger candidate and a stronger networking engineer.

Tomorrow, we'll take a look at CHAP, and why routers cannot use the same password on both ends of the link.

Keep studying!

Chris Bryant


CCIE ? #12933


chris@thebryantadvantage.com

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 chris@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 and study aids, 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

Rolling Meadows Cadillac Escalade rental .. Lockport Chicago limo O’Hare
In The News:

These 35 Chrome extensions have privacy and security concerns. Tech expert Kurt “CyberGuy" Knutsson says to delete them now.
Tech expert Kurt “CyberGuy" Knutsson says 329,000 mph fusion rocket promises to be fast, disruptive and enable deep-space missions.
Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.
Tech expert Kurt “CyberGuy" Knutsson says a new autonomous AI is a game changer that also raises privacy risks. Is your data safe?
Tech expert Kurt “CyberGuy" Knutsson says robots and drones are revolutionizing fruit farming with faster picking and smarter handling.
Landmark Admin revises May 2024 cyberattack scope to show twice as many people were affected. Kurt “CyberGuy" Knutsson gives tips to help stay safe from an insurance data breach.
Tech expert Kurt “CyberGuy" Knutsson talks about how Yamaha’s hydrogen outboard motor could revolutionize boating with zero emissions.
Tech expert Kurt “CyberGuy" Knutsson reveals how to memorialize or remove a deceased loved one’s Facebook account and protect their digital legacy from misuse or scams.
Tech expert Kurt “CyberGuy" Knutsson says an Apple Watch saved psychiatrist Amanda Faulkner by detecting deadly leukemia early.
Scammers and fraudsters are increasingly targeting the most vulnerable, especially nursing homes and the personal data of their residents. Kurt the CyberGuy has safety tips.
Infected USB flash drives can spread malware among multiple organizations in ways that can easily bypass traditional security systems.
With a fully automated warehouse system and AI-powered robots, Ocado's Hive picks, packs and delivers grocery store orders in just a few minutes.
Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.
Recycling robots are using artificial intelligence to learn how to sort recyclables by recognizing patterns in colors, textures, shapes and logos.
The Reachy 2 robot is designed to be friendly and approachable, inviting natural interaction and is perfect for research, education and experimenting with embodied AI.
Kurt "CyberGuy" Knutsson shares several easy ways to keep your credit cards safe from digital thieves while you're traveling this summer.
Arcturus sets up cameras around the edges of baseball stadiums to capture real-time action and generate a 3D digital clone of the game.
Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.
The CyberGuy explains why healthcare organizations are vulnerable to hackers after there have been a half dozen data breaches this year.
Developed at two California universities, the innovative technology combines brain-computer interfaces with advanced AI to decode neural activity into audible speech.
Microsoft patches 12 critical flaws, but six have already been exploited by criminals. Kurt “CyberGuy" Knutsson says updating your system is only a short-term fix.
Tech expert Kurt “CyberGuy" Knutsson discusses how robots can milk, feed and clean cows on dairy farms, boosting efficiency and comfort.
Tech expert Kurt “CyberGuy" Knutsson says quantum internet ensures unhackable security and redefines online privacy and speed.
Kawasaki's CORLEO is a hydrogen-powered, AI-driven rideable robot. Tech expert Kurt “CyberGuy" Knutsson reports on this new way of thinking about off-road transportation.
The CyberGuy breaks down five mobile privacy terms that could make a difference when it comes to keeping your personal information safe.

Lotus Domino Implementation and Development: Infrastructure ? Present and Future

Domino server is a buffer between the operation system and... Read More

Databases ? How We Love to Hate Them!

You've finally created databases that you can actually use to... Read More

Microsoft Great Plains Dynamics on Pervasive SQL.2000 Data Repair ? Overview For DBAs

Some introduction into Great Plains Software products, now Microsoft Business... Read More

Simple Solution for Php Includes - IFrames

I have recently created my first Php program. I wanted... Read More

Blind CC (Bcc): Master Its Use When E-Mailing

If you use Microsoft Outlook (or similar applications) for e-mailing,... Read More

Free Preventive Maintenance Software

While several preventive maintenance software manufacturers offer free trials for... Read More

Microsoft Great Plains Upgrade ? Version 8.0 Overview for IT Director/Controller

If you have Microsoft Great Plains as main accounting and... Read More

Groupware Finds Home in American Business: Collaboration Tool Analysis

What is Groupware?Have you ever had to manage document collaboration... Read More

Microsoft Great Plains: Getting New Users Licenses ? Annual Service Plan FAQ

Microsoft Business Solutions Great Plains, Solomon, Navision, Axapta, Microsoft CRM... Read More

Is Your Computer Sick?

Viruses and spyware usually show up on your computer one... Read More

EDI: Electronic Document Interchange for Microsoft Great Plains ? Overview for Software Developer/Pr

Microsoft Great Plains - Microsoft Business Solutions accounting and ERP... Read More

XML Parser and Their Types

XML parser is a software module to read documents and... Read More

Microsoft CRM Integration with Microsoft Retail Management System (RMS) ? Overview

Microsoft Client Relation Management system (Microsoft CRM) and Microsoft RMS... Read More

How to Choose the BEST Charting Software

I suggest that you do not spend a lot of... Read More

Fundraising Software ? How Can That Help Me?

Fundraising software lets you connect with donors in a way... Read More

Great Plains Dexterity: Customizations & Source Code Programming

Great Plains Software Dynamics, Dynamics C/S+, eEnterprise were written on... Read More

The Importance of Timely Timesheets

Whether you are a small consultancy firm, a medium sized... Read More

Software Development in 2005 - Back to the Future

2005 ? Back to the Future.What does the future hold?... Read More

Reloading Windows XP

If you have been running Windows XP for a couple... Read More

Software Review: Xsitepro Total Site Management Software

It's not very often I get excited about a software... Read More

HelpDesk & Asset Management Software - Choosing The Right One

If you are to buy a HelpDesk & Asset Management... Read More

The Tools and Features of Adobe Photoshop

Adobe Photoshop is one of the world's leading graphics editing... Read More

CROOK: A Methodology for the Refinement of Forward-Error Correction

Table of Contents1) Introduction 2) Related Work 3) Framework 4)... Read More

Microsoft Great Plains Beverage Production & Distribution ? Implementation & Customization Highlight

Microsoft Business Solutions Great Plains has many years of successful... Read More

Open Source Concepts: Dual Licensing Explained

We were recently faced with a decision: either to let... Read More

Des Moines rental limo ..