Software informational articles

Cisco certification: foreword to isdn, part iii - software


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 qualifications candidates must be common with are PAP and CHAP.

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

Regarding both PAP and CHAP, it‚??s a conventional confusion that each side must substantiate the other. PAP and CHAP both assist bidirectional and unidirectional certification that is, R1 can substantiate R2 devoid of R2 of necessity authenticating R1. It‚??s more communal to use unidirectional confirmation in a lab ecosystem than a creation network, but keep in mind that bidirectional certification is an option, not a requirement.

The configurations of PAP and CHAP do have their similarities. For both, you‚??ll configure a username/password amalgamation in large-scale configuration mode. Newcomers to ISDN at times put the local router name in for the username bear in mind that the cold router name is the username.

The only real improvement of PAP over CHAP comes in the password configuration. Since PAP in point of fact sends the password as a whole over the link, the two routers can send atypical passwords at some point in authentication. The business 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 certification pap. So far, your confirmation chart looks like this:

username R2 password CCNA

Int bri0

encapsulation ppp

ppp confirmation pap

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

Int bri0

encapsulation ppp

ppp certification pap

ppp pap sent-username R1 password CISCO

I at all times further CCNA and CCNP candidates to use as many debugs as doable when operational in their lab, since these guidelines show us how equipment work. For any PPP authentication, at all times run debug ppp negotiation already conveyance appealing travel to trigger the call. Examination just how PAP and CHAP work give you a much change for the better agreement of what‚??s going on ‚??behind the command‚??, and makes you a stronger applicant 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 dynamic in the Cisco qualifications area 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 efficient 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 collect the creature awareness they deserve. Module are accessible over the Internet and in anyone in choose cities. Chris has custom-written the Study Guide and Lab Course book used in each classes - no third-party guidance resources 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 in print for myself by Chris. Chris is all the time glad to hear from Cisco guarantee candidates at chris@thebryantadvantage. com.

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