Intel ER8100STUS - Express 8100 Router, Reference Manual

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Reference.bok : Chapter02 15 Wed Apr 22 10:58:08 1998
15
Point-to-Point Protocol (PPP)
Leased Lines Links
3 Device 1 compares the locally encrypted text file with the text file
encrypted by Device 2. If the text files are the same (Password 1 = Pass-
word 2) Device 2 is authenticated. Otherwise, Device 2 is not authenticated
and data communications with Device 2 are not allowed.
Peer Authentication using the Password Authentication Protocol
(PAP)
Introduction to PAP
The Password Authentication Protocol (PAP) can be used as an alternative to
CHAP to provide link security against unauthorized access. PAP uses simple
password protection against unauthorized access.
PAP versus CHAP
CHAP uses password encryption to authenticate peers and the passwords are
never transmitted directly over the PPP link, and therefore cannot be intercepted
and used by unauthorized sources. PAP uses simple password protection where
the password is transmitted directly over the link—PAP is therefore not resilient
to link monitoring.
Note
For the best security, you should use CHAP rather than PAP for link
access protection wherever possible.
PAP can however be used when it is the only authentication protocol supported
by the remote device.
Replies to PAP requests
A device (for example the Intel Express 8100 Router) always tries to reply to a
request for authentication from a peer, using the password defined for the User
ID of the peer.
Device 1
PPP Link
1337
Peer is
authenticated
Peer is NOT
authenticated
Device 2
Random
text file
encrypted
Device 1
Random
text file
encrypted
Device 1
Random
text file
encrypted
Device 2
Random
text file
encrypted
Device 2
=
=