Руководство Пользователя для Netopia 2e-h-w

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How Your Cayman 2E-H-W Works
Cayman 2E-H-W User’s Guide
C-8
November 2000
Authentication 
The PPP protocol suite includes two optional methods (Password 
Authentication Protocol (PAP) and Challenge Handshake 
Authentication Protocol (CHAP)) to ensure that unauthorized users 
do not access network services. By default, authentication is not 
required as part of the PPP link process. However if a peer requires 
authentication, it must negotiate the use of an authentication 
protocol during the link establishment phase.
The manner in which each peer will authenticate the other is 
negotiated during the link configuration phase, when each peer 
specifies whether it requires authentication and, if it does, the 
authentication method it uses. If a link peer requires authentication 
(if it is an authenticator, in the terminology of RFC 1334), the other 
peer must submit its name and authentication information before 
the link can proceed. If the peer fails to send valid authentication 
information, the authenticator terminates (closes) the PPP link.
The authentication method used by one peer can be different from 
the authentication method used by the other peer. For example, a 
peer at one end of a link may require authentication while the other 
end of the link may not. Similarly, one end of a link may use PAP to 
authenticate peers while the other end uses CHAP.
A PPP interface can support one or both authentication methods. If 
you specify that a serial port must use one method but not the other, 
the remote peer must authenticate itself according to the specified 
authentication protocol. If you specify that a serial port can use 
either CHAP or PAP to authenticate a remote peer (that is, both 
CHAP and PAP are enabled), the router tries to use CHAP to 
authenticate connection requests. If the remote peer does not 
support CHAP, the router requires that the remote peer use PAP to 
authenticate itself.
Password Authentication Protocol (PAP) – The Password 
Authentication Protocol (PAP) provides a simple method for a 
peer to establish its identity. A peer being authenticated with 
PAP sends Authentication Request messages that contain its 
name and PAP password until the authenticator acknowledges