PPP with MPPE question (rfc3078) - PPP

This is a discussion on PPP with MPPE question (rfc3078) - PPP ; Hi, Will appreciate some help for the below questions. 1. When PPP is used with MPPE, rfc3078 says the below about the Encryted data field in the packet format (See section 3.1). " Encrypted Data The encrypted data begins with ...

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  1. PPP with MPPE question (rfc3078)

    Hi,
    Will appreciate some help for the below questions.
    1. When PPP is used with MPPE, rfc3078 says the below about the Encryted
    data field in the packet format (See section 3.1).
    "
    Encrypted Data

    The encrypted data begins with the protocol field. For
    example, in case of an IP packet (0x0021 followed by an IP
    header), the MPPE processor will first encrypt the protocol
    field and then encrypt the IP header.

    If the packet contains header compression, the MPPE processor
    is applied AFTER header compression is performed and MUST be
    applied to the compressed header as well. For example, if a
    packet contained the protocol type 0x002D (for a compressed
    TCP/IP header), the MPPE processor would first encrypt 0x002D
    and then it would encrypt the compressed Van-Jacobsen TCP/IP
    header.

    "

    Does this mean only the IP header is encrypted or the whole IP packet is
    encrypted.. ?
    Regards
    Shashank





    --
    Regards
    Shashank
    http://mia.ece.uic.edu/~papers



  2. Re: PPP with MPPE question (rfc3078)

    "Shashank Khanvilkar" writes:
    > Does this mean only the IP header is encrypted or the whole IP packet is
    > encrypted.. ?


    The whole IP packet is encrypted.

    What it means is that if you start with this from the IP stack:



    then you should first run it through VJ compression (if you're using
    that) to produce:



    and then run the whole sequence (the header plus the )
    through the encryption algorithm to produce the datagram to send to
    the peer.

    --
    James Carlson, Solaris Networking
    Sun Microsystems / 1 Network Drive 71.234W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.497N Fax +1 781 442 1677

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