Please Whitelist This Site?
I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :)
If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads.
If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK.
Thanks for your understanding!
Sincerely, Charles Kozierok
Author and Publisher, The TCP/IP Guide
NOTE: Using software to mass-download the site degrades the server and is prohibited.
If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.
PPP Authentication Protocols: Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP)
(Page 1 of 3)
PPP was designed to provide layer
two connectivity over a variety of serial links and other physical layer
technologies, some of which have much more of a concern about security
than others. For example, suppose you hook two machines in your computer
lab together with a serial cable and want to run PPP between them. When
one of these initiates a PPP link with the other, you don't really need
to worry about who's calling. On the other hand, consider
an Internet Service Provider using PPP for remote dial-in users. They
generally want to allow only their customers to connect, not just anyone.
The PPP protocol suite was designed
to include the use of an optional authentication protocol for links
where authentication is important. During basic link setup by LCP,
devices can negotiate the use of an authentication protocol. If they
agree, after the LCP link is set up a series of authentication messages
are sent to verify the identity of the device initiating the link. Only
if authentication is successful can the link configuration proceed.
The PPP suite initially defined two
different authentication protocols: the Password Authentication Protocol
(PAP) and Challenge Handshake Authentication Protocol (CHAP).
Note: Incidentally, in addition to PAP and CHAP, it is possible to use proprietary authentication schemes. This requires that the appropriate configuration option values be programmed into LCP for placement in the Authentication-Protocol configuration option.
|If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!|
Table Of Contents - Contact Us
The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005
© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.