Home
>
Software
>
Cisco Certification: Introduction To ISDN, Part III

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 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!

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 http://www.thebryantadvantage.com.

same day cleaning service Des Plaines ..

In The News:

New iPhone replacement scam uses pressure tactics and fake carrier calls to steal devices from buyers. Criminals claim shipping errors and demand urgent returns.

Amazon Ring's new facial recognition feature sparks privacy controversy as Electronic Frontier Foundation critics argue the AI upgrade expands surveillance risks.

New Android banking trojan Sturnus steals credentials, reads encrypted messages and controls devices.

Denmark's 3D-printed student village proves automation builds 36 apartments faster than traditional methods. Skovsporet project shows housing future.

Discover Android's new Sound Notifications feature that alerts you to smoke alarms, doorbells, and baby cries even when wearing headphones.

New SantaStealer malware reportedly threatens holiday shoppers with password theft. This Christmas-themed info-stealer targets browsers and crypto wallets.

The Christmas season brings a surge in Netflix phishing scams targeting shoppers with fake emails. Stacey P received convincing scam but verified account first.

San Francisco Giants invite Jamie Grohsong to throw ceremonial first pitch at Oracle Park after he learned to play baseball with a bionic hand following an injury.

FBI warns cybercriminals are stealing family photos from social media to create fake proof of life images in virtual kidnapping scams targeting victims.

Instagram's new 'Your Algorithm' tool lets you control your Reels feed in real time. The app now gives you power to customize what videos you see.

Major Marquis fintech breach exposes 400,000-plus Americans' data through unpatched SonicWall vulnerability, with Texas hardest hit at 354,000 affected.

Free up iPhone storage fast by clearing large photos and videos from Messages app. Simple steps for iOS users to delete attachments without losing chats.

Scammers are flooding inboxes with fake tracking alerts that mimic real carriers, exploiting the holiday rush to steal logins and personal data.

The Fox News AI Newsletter brings you the latest news on AI technology advancements and the challenges and opportunities AI presents now and for the future.

Texas family reunites with missing 11-year-old cat Grayson after 103 days using Petco Love Lost's AI photo matching technology and community help.

Tired of AI customer service loops? These insider tricks help you escape "frustration AI" and get real human help when you need it most for urgent issues.

Unlock richer audio from your streaming apps with simple tweaks to volume normalization, equalizer settings, and quality preferences for cleaner sound.

Scammers are sending fake Facebook settlement payout emails that mimic legitimate notices from the privacy settlement administrator to deceive users.

Holiday shopping scams surge as fake refund emails target distracted consumers during Black Friday and holiday seasons, costing Americans billions annually.

The AI-powered IRMO M1 exoskeleton features four modes, including turbo, eco, training and rest for hiking, running, cycling and sports with eight-hour battery life.

OpenAI announced upgrades for its ChatGPT Images platform on Tuesday, saying the program can now make more precise edits and produce images more quickly.

Chrome for Android now turns web articles into AI-powered podcast conversations. Get hands-free browsing with Google Gemini's natural audio summaries.

LastPass faces $1.6 million fine from U.K. regulators after 2022 data breach exposed 1.6 million users. Password manager failed proper security controls.

Petco disclosed a data breach exposing customer Social Security numbers, financial account details, and driver's license information due to a software error.

Baseball teams can now analyze complete swing mechanics in normal training environments using Theia's markerless AI system that processes standard high-speed footage.

Cisco Certification: Introduction To ISDN, Part III

Software