Software informational articles

Establishment to isdn, part iii: pap - software


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 substantiation schemes. The two methods Cisco guarantee candidates must be customary with are PAP and CHAP.

Password Certification Protocol (PAP) sends the username and password over the ISDN link in clear-text. Distribution any passwords over any WAN link in clear-text is in the main a bad idea, but it's critical to know you have this option.

Regarding both PAP and CHAP, it's a conventional confusion that each side must endorse the other. PAP and CHAP both aid bidirectional and unidirectional authentication; that is, R1 can endorse R2 not including R2 automatically authenticating R1. It's more customary to use unidirectional confirmation in a lab ecosystem than a fabrication network, but keep in mind that bidirectional substantiation is an option, not a requirement.

The configurations of PAP and CHAP do have their similarities. For both, you'll configure a username/password blend in inclusive configuration mode. Newcomers to ISDN every now and then put the local router name in for the username; bear in mind that the apart router name is the username.

The only real benefit of PAP over CHAP comes in the password configuration. Since PAP in fact sends the password as a whole over the link, the two routers can send atypical passwords for the duration of authentication. The action 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 endorsement pap. So far, your endorsement design looks like this:

username R2 password CCNA

Int bri0

encapsulation ppp

ppp certification pap

PAP requires an extra appreciation at this point. The ppp pap sent-username appreciation is essential under the interface, indicating the username and password this router will be carriage to the apart router.

Int bri0

encapsulation ppp

ppp substantiation pap

ppp pap sent-username R1 password CISCO

I all the time further CCNA and CCNP candidates to use as many debugs as achievable when effective in their lab, since these guidelines show us how effects work. For any PPP authentication, continually run debug ppp negotiation ahead of transfer appealing transfer to trigger the call. Inspection accurately how PAP and CHAP work give you a much develop accepting of what's going on "behind the command", and makes you a stronger contestant 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 effective in the Cisco qualifications convergence 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 actual 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 be given the character awareness they deserve. Module are obtainable over the Internet and in character in cliquey cities. Chris has custom-written the Study Guide and Lab Schoolbook used in each classes - no third-party exercise equipment 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 in black and white for myself by Chris. Chris is continually glad to hear from Cisco qualifications candidates at chris@thebryantadvantage. com

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