IP-CHAP

Reference standard: RFC 1334.

After the link has been established by the LCP, PPP provides for an optional Authentication phase before proceeding to the network-layer protocol phase. If authentication of the link is desired, an implementation MUST specify the Authentication-Protocol Configuration Option during link establishment phase (by the LCP).

Exactly one CHAP packet is encapsulated in the PPP Information field, where the PPP Protocol field indicates type hex c223 (Challenge-Handshake Authentication Protocol).

Packet structure: fields

bits 0 _ _ _ _ _ _ 7 field
octet 1 Code
octet 2 Identifier
The identifier field aids in matching requests and replies.
octets 3-4 Length
The length field indicates the length of the CHAP packet including the Code, Identifier, Length and Data fields.
octets 5-n Data
The data field is zero or more octets.

Bit 0 is the most significant bit.

Code

bits 0 _ _ _ _ _ _ 7 Dec Code designation
0 0 0 0 0 0 0 1 1 Challenge
0 0 0 0 0 0 1 0 2 Response
0 0 0 0 0 0 1 1 3 Success
0 0 0 0 0 1 0 0 4 Failure

 

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updated:  27-Feb-04