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RFC 2865

 
 
 

Remote Authentication Dial In User Service (RADIUS)

Part 2 of 3, p. 22 to 50
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5.  Attributes

   RADIUS Attributes carry the specific authentication, authorization,
   information and configuration details for the request and reply.

   The end of the list of Attributes is indicated by the Length of the
   RADIUS packet.

   Some Attributes MAY be included more than once.  The effect of this
   is Attribute specific, and is specified in each Attribute
   description.  A summary table is provided at the end of the
   "Attributes" section.

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   If multiple Attributes with the same Type are present, the order of
   Attributes with the same Type MUST be preserved by any proxies.  The
   order of Attributes of different Types is not required to be
   preserved.  A RADIUS server or client MUST NOT have any dependencies
   on the order of attributes of different types.  A RADIUS server or
   client MUST NOT require attributes of the same type to be contiguous.

   Where an Attribute's description limits which kinds of packet it can
   be contained in, this applies only to the packet types defined in
   this document, namely Access-Request, Access-Accept, Access-Reject
   and Access-Challenge (Codes 1, 2, 3, and 11).  Other documents
   defining other packet types may also use Attributes described here.
   To determine which Attributes are allowed in Accounting-Request and
   Accounting-Response packets (Codes 4 and 5) refer to the RADIUS
   Accounting document [5].

   Likewise where packet types defined here state that only certain
   Attributes are permissible in them, future memos defining new
   Attributes should indicate which packet types the new Attributes may
   be present in.

   A summary of the Attribute format is shown below.  The fields are
   transmitted from left to right.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
   |     Type      |    Length     |  Value ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

   Type

      The Type field is one octet.  Up-to-date values of the RADIUS Type
      field are specified in the most recent "Assigned Numbers" RFC [6].
      Values 192-223 are reserved for experimental use, values 224-240
      are reserved for implementation-specific use, and values 241-255
      are reserved and should not be used.

      A RADIUS server MAY ignore Attributes with an unknown Type.

      A RADIUS client MAY ignore Attributes with an unknown Type.

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      This specification concerns the following values:

          1      User-Name
          2      User-Password
          3      CHAP-Password
          4      NAS-IP-Address
          5      NAS-Port
          6      Service-Type
          7      Framed-Protocol
          8      Framed-IP-Address
          9      Framed-IP-Netmask
         10      Framed-Routing
         11      Filter-Id
         12      Framed-MTU
         13      Framed-Compression
         14      Login-IP-Host
         15      Login-Service
         16      Login-TCP-Port
         17      (unassigned)
         18      Reply-Message
         19      Callback-Number
         20      Callback-Id
         21      (unassigned)
         22      Framed-Route
         23      Framed-IPX-Network
         24      State
         25      Class
         26      Vendor-Specific
         27      Session-Timeout
         28      Idle-Timeout
         29      Termination-Action
         30      Called-Station-Id
         31      Calling-Station-Id
         32      NAS-Identifier
         33      Proxy-State
         34      Login-LAT-Service
         35      Login-LAT-Node
         36      Login-LAT-Group
         37      Framed-AppleTalk-Link
         38      Framed-AppleTalk-Network
         39      Framed-AppleTalk-Zone
         40-59   (reserved for accounting)
         60      CHAP-Challenge
         61      NAS-Port-Type
         62      Port-Limit
         63      Login-LAT-Port

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   Length

      The Length field is one octet, and indicates the length of this
      Attribute including the Type, Length and Value fields.  If an
      Attribute is received in an Access-Request but with an invalid
      Length, an Access-Reject SHOULD be transmitted.  If an Attribute
      is received in an Access-Accept, Access-Reject or Access-Challenge
      packet with an invalid length, the packet MUST either be treated
      as an Access-Reject or else silently discarded.

   Value

      The Value field is zero or more octets and contains information
      specific to the Attribute.  The format and length of the Value
      field is determined by the Type and Length fields.

      Note that none of the types in RADIUS terminate with a NUL (hex
      00).  In particular, types "text" and "string" in RADIUS do not
      terminate with a NUL (hex 00).  The Attribute has a length field
      and does not use a terminator.  Text contains UTF-8 encoded 10646
      [7] characters and String contains 8-bit binary data.  Servers and
      servers and clients MUST be able to deal with embedded nulls.
      RADIUS implementers using C are cautioned not to use strcpy() when
      handling strings.

      The format of the value field is one of five data types.  Note
      that type "text" is a subset of type "string".

      text      1-253 octets containing UTF-8 encoded 10646 [7]
                characters.  Text of length zero (0) MUST NOT be sent;
                omit the entire attribute instead.

      string    1-253 octets containing binary data (values 0 through
                255 decimal, inclusive).  Strings of length zero (0)
                MUST NOT be sent; omit the entire attribute instead.

      address   32 bit value, most significant octet first.

      integer   32 bit unsigned value, most significant octet first.

      time      32 bit unsigned value, most significant octet first --
                seconds since 00:00:00 UTC, January 1, 1970.  The
                standard Attributes do not use this data type but it is
                presented here for possible use in future attributes.

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5.1.  User-Name

   Description

      This Attribute indicates the name of the user to be authenticated.
      It MUST be sent in Access-Request packets if available.

      It MAY be sent in an Access-Accept packet, in which case the
      client SHOULD use the name returned in the Access-Accept packet in
      all Accounting-Request packets for this session.  If the Access-
      Accept includes Service-Type = Rlogin and the User-Name attribute,
      a NAS MAY use the returned User-Name when performing the Rlogin
      function.

   A summary of the User-Name Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
   |     Type      |    Length     |  String ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

   Type

      1 for User-Name.

   Length

      >= 3

   String

      The String field is one or more octets.  The NAS may limit the
      maximum length of the User-Name but the ability to handle at least
      63 octets is recommended.

      The format of the username MAY be one of several forms:

      text      Consisting only of UTF-8 encoded 10646 [7] characters.

      network access identifier
                A Network Access Identifier as described in RFC 2486
                [8].

      distinguished name
                A name in ASN.1 form used in Public Key authentication
                systems.

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5.2.  User-Password

   Description

      This Attribute indicates the password of the user to be
      authenticated, or the user's input following an Access-Challenge.
      It is only used in Access-Request packets.

      On transmission, the password is hidden.  The password is first
      padded at the end with nulls to a multiple of 16 octets.  A one-
      way MD5 hash is calculated over a stream of octets consisting of
      the shared secret followed by the Request Authenticator.  This
      value is XORed with the first 16 octet segment of the password and
      placed in the first 16 octets of the String field of the User-
      Password Attribute.

      If the password is longer than 16 characters, a second one-way MD5
      hash is calculated over a stream of octets consisting of the
      shared secret followed by the result of the first xor.  That hash
      is XORed with the second 16 octet segment of the password and
      placed in the second 16 octets of the String field of the User-
      Password Attribute.

      If necessary, this operation is repeated, with each xor result
      being used along with the shared secret to generate the next hash
      to xor the next segment of the password, to no more than 128
      characters.

      The method is taken from the book "Network Security" by Kaufman,
      Perlman and Speciner [9] pages 109-110.  A more precise
      explanation of the method follows:

      Call the shared secret S and the pseudo-random 128-bit Request
      Authenticator RA.  Break the password into 16-octet chunks p1, p2,
      etc.  with the last one padded at the end with nulls to a 16-octet
      boundary.  Call the ciphertext blocks c(1), c(2), etc.  We'll need
      intermediate values b1, b2, etc.

         b1 = MD5(S + RA)       c(1) = p1 xor b1
         b2 = MD5(S + c(1))     c(2) = p2 xor b2
                .                       .
                .                       .
                .                       .
         bi = MD5(S + c(i-1))   c(i) = pi xor bi

      The String will contain c(1)+c(2)+...+c(i) where + denotes
      concatenation.

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      On receipt, the process is reversed to yield the original
      password.

   A summary of the User-Password Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
   |     Type      |    Length     |  String ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

   Type

      2 for User-Password.

   Length

      At least 18 and no larger than 130.

   String

      The String field is between 16 and 128 octets long, inclusive.

5.3.  CHAP-Password

   Description

      This Attribute indicates the response value provided by a PPP
      Challenge-Handshake Authentication Protocol (CHAP) user in
      response to the challenge.  It is only used in Access-Request
      packets.

      The CHAP challenge value is found in the CHAP-Challenge Attribute
      (60) if present in the packet, otherwise in the Request
      Authenticator field.

   A summary of the CHAP-Password Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
   |     Type      |    Length     |  CHAP Ident   |  String ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

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   Type

      3 for CHAP-Password.

   Length

      19

   CHAP Ident

      This field is one octet, and contains the CHAP Identifier from the
      user's CHAP Response.

   String

      The String field is 16 octets, and contains the CHAP Response from
      the user.

5.4.  NAS-IP-Address

   Description

      This Attribute indicates the identifying IP Address of the NAS
      which is requesting authentication of the user, and SHOULD be
      unique to the NAS within the scope of the RADIUS server. NAS-IP-
      Address is only used in Access-Request packets.  Either NAS-IP-
      Address or NAS-Identifier MUST be present in an Access-Request
      packet.

      Note that NAS-IP-Address MUST NOT be used to select the shared
      secret used to authenticate the request.  The source IP address of
      the Access-Request packet MUST be used to select the shared
      secret.

   A summary of the NAS-IP-Address Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |            Address
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            Address (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      4 for NAS-IP-Address.

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   Length

      6

   Address

      The Address field is four octets.

5.5.  NAS-Port

   Description

      This Attribute indicates the physical port number of the NAS which
      is authenticating the user.  It is only used in Access-Request
      packets.  Note that this is using "port" in its sense of a
      physical connection on the NAS, not in the sense of a TCP or UDP
      port number.  Either NAS-Port or NAS-Port-Type (61) or both SHOULD
      be present in an Access-Request packet, if the NAS differentiates
      among its ports.

   A summary of the NAS-Port Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      5 for NAS-Port.

   Length

      6

   Value

      The Value field is four octets.

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5.6.  Service-Type

   Description

      This Attribute indicates the type of service the user has
      requested, or the type of service to be provided.  It MAY be used
      in both Access-Request and Access-Accept packets.  A NAS is not
      required to implement all of these service types, and MUST treat
      unknown or unsupported Service-Types as though an Access-Reject
      had been received instead.

   A summary of the Service-Type Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      6 for Service-Type.

   Length

      6

   Value

      The Value field is four octets.

       1      Login
       2      Framed
       3      Callback Login
       4      Callback Framed
       5      Outbound
       6      Administrative
       7      NAS Prompt
       8      Authenticate Only
       9      Callback NAS Prompt
      10      Call Check
      11      Callback Administrative

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      The service types are defined as follows when used in an Access-
      Accept.  When used in an Access-Request, they MAY be considered to
      be a hint to the RADIUS server that the NAS has reason to believe
      the user would prefer the kind of service indicated, but the
      server is not required to honor the hint.

      Login               The user should be connected to a host.

      Framed              A Framed Protocol should be started for the
                          User, such as PPP or SLIP.

      Callback Login      The user should be disconnected and called
                          back, then connected to a host.

      Callback Framed     The user should be disconnected and called
                          back, then a Framed Protocol should be started
                          for the User, such as PPP or SLIP.

      Outbound            The user should be granted access to outgoing
                          devices.

      Administrative      The user should be granted access to the
                          administrative interface to the NAS from which
                          privileged commands can be executed.

      NAS Prompt          The user should be provided a command prompt
                          on the NAS from which non-privileged commands
                          can be executed.

      Authenticate Only   Only Authentication is requested, and no
                          authorization information needs to be returned
                          in the Access-Accept (typically used by proxy
                          servers rather than the NAS itself).

      Callback NAS Prompt The user should be disconnected and called
                          back, then provided a command prompt on the
                          NAS from which non-privileged commands can be
                          executed.

      Call Check          Used by the NAS in an Access-Request packet to
                          indicate that a call is being received and
                          that the RADIUS server should send back an
                          Access-Accept to answer the call, or an
                          Access-Reject to not accept the call,
                          typically based on the Called-Station-Id or
                          Calling-Station-Id attributes.  It is

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                          recommended that such Access-Requests use the
                          value of Calling-Station-Id as the value of
                          the User-Name.

      Callback Administrative
                          The user should be disconnected and called
                          back, then granted access to the
                          administrative interface to the NAS from which
                          privileged commands can be executed.

5.7.  Framed-Protocol

   Description

      This Attribute indicates the framing to be used for framed access.
      It MAY be used in both Access-Request and Access-Accept packets.

   A summary of the Framed-Protocol Attribute format is shown below.
   The fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      7 for Framed-Protocol.

   Length

      6

   Value

      The Value field is four octets.

      1      PPP
      2      SLIP
      3      AppleTalk Remote Access Protocol (ARAP)
      4      Gandalf proprietary SingleLink/MultiLink protocol
      5      Xylogics proprietary IPX/SLIP
      6      X.75 Synchronous

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5.8.  Framed-IP-Address

   Description

      This Attribute indicates the address to be configured for the
      user.  It MAY be used in Access-Accept packets.  It MAY be used in
      an Access-Request packet as a hint by the NAS to the server that
      it would prefer that address, but the server is not required to
      honor the hint.

   A summary of the Framed-IP-Address Attribute format is shown below.
   The fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |            Address
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            Address (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      8 for Framed-IP-Address.

   Length

      6

   Address

      The Address field is four octets.  The value 0xFFFFFFFF indicates
      that the NAS Should allow the user to select an address (e.g.
      Negotiated).  The value 0xFFFFFFFE indicates that the NAS should
      select an address for the user (e.g. Assigned from a pool of
      addresses kept by the NAS).  Other valid values indicate that the
      NAS should use that value as the user's IP address.

5.9.  Framed-IP-Netmask

   Description

      This Attribute indicates the IP netmask to be configured for the
      user when the user is a router to a network.  It MAY be used in
      Access-Accept packets.  It MAY be used in an Access-Request packet
      as a hint by the NAS to the server that it would prefer that
      netmask, but the server is not required to honor the hint.

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   A summary of the Framed-IP-Netmask Attribute format is shown below.
   The fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |            Address
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            Address (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      9 for Framed-IP-Netmask.

   Length

      6

   Address

      The Address field is four octets specifying the IP netmask of the
      user.

5.10.  Framed-Routing

   Description

      This Attribute indicates the routing method for the user, when the
      user is a router to a network.  It is only used in Access-Accept
      packets.

   A summary of the Framed-Routing Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      10 for Framed-Routing.

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   Length

      6

   Value

      The Value field is four octets.

       0      None
       1      Send routing packets
       2      Listen for routing packets
       3      Send and Listen

5.11.  Filter-Id

   Description

      This Attribute indicates the name of the filter list for this
      user.  Zero or more Filter-Id attributes MAY be sent in an
      Access-Accept packet.

      Identifying a filter list by name allows the filter to be used on
      different NASes without regard to filter-list implementation
      details.

   A summary of the Filter-Id Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
   |     Type      |    Length     |  Text ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

   Type

      11 for Filter-Id.

   Length

      >= 3

   Text

      The Text field is one or more octets, and its contents are
      implementation dependent.  It is intended to be human readable and
      MUST NOT affect operation of the protocol.  It is recommended that
      the message contain UTF-8 encoded 10646 [7] characters.

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5.12.  Framed-MTU

   Description

      This Attribute indicates the Maximum Transmission Unit to be
      configured for the user, when it is not negotiated by some other
      means (such as PPP).  It MAY be used in Access-Accept packets.  It
      MAY be used in an Access-Request packet as a hint by the NAS to
      the server that it would prefer that value, but the server is not
      required to honor the hint.

   A summary of the Framed-MTU Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      12 for Framed-MTU.

   Length

      6

   Value

      The Value field is four octets.  Despite the size of the field,
      values range from 64 to 65535.

5.13.  Framed-Compression

   Description

      This Attribute indicates a compression protocol to be used for the
      link.  It MAY be used in Access-Accept packets.  It MAY be used in
      an Access-Request packet as a hint to the server that the NAS
      would prefer to use that compression, but the server is not
      required to honor the hint.

      More than one compression protocol Attribute MAY be sent.  It is
      the responsibility of the NAS to apply the proper compression
      protocol to appropriate link traffic.

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   A summary of the Framed-Compression Attribute format is shown below.
   The fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      13 for Framed-Compression.

   Length

      6

   Value

      The Value field is four octets.

       0      None
       1      VJ TCP/IP header compression [10]
       2      IPX header compression
       3      Stac-LZS compression

5.14.  Login-IP-Host

   Description

      This Attribute indicates the system with which to connect the user,
      when the Login-Service Attribute is included.  It MAY be used in
      Access-Accept packets.  It MAY be used in an Access-Request packet as
      a hint to the server that the NAS would prefer to use that host, but
      the server is not required to honor the hint.

   A summary of the Login-IP-Host Attribute format is shown below.  The
   fields are transmitted from left to right.

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    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |            Address
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            Address (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      14 for Login-IP-Host.

   Length

      6

   Address

      The Address field is four octets.  The value 0xFFFFFFFF indicates
      that the NAS SHOULD allow the user to select an address.  The
      value 0 indicates that the NAS SHOULD select a host to connect the
      user to.  Other values indicate the address the NAS SHOULD connect
      the user to.

5.15.  Login-Service

   Description

      This Attribute indicates the service to use to connect the user to
      the login host.  It is only used in Access-Accept packets.

   A summary of the Login-Service Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      15 for Login-Service.

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   Length

      6

   Value

      The Value field is four octets.

       0   Telnet
       1   Rlogin
       2   TCP Clear
       3   PortMaster (proprietary)
       4   LAT
       5   X25-PAD
       6   X25-T3POS
       8   TCP Clear Quiet (suppresses any NAS-generated connect string)

5.16.  Login-TCP-Port

   Description

      This Attribute indicates the TCP port with which the user is to be
      connected, when the Login-Service Attribute is also present.  It
      is only used in Access-Accept packets.

   A summary of the Login-TCP-Port Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      16 for Login-TCP-Port.

   Length

      6

   Value

      The Value field is four octets.  Despite the size of the field,
      values range from 0 to 65535.

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5.17.  (unassigned)

   Description

      ATTRIBUTE TYPE 17 HAS NOT BEEN ASSIGNED.

5.18.  Reply-Message

   Description

      This Attribute indicates text which MAY be displayed to the user.

      When used in an Access-Accept, it is the success message.

      When used in an Access-Reject, it is the failure message.  It MAY
      indicate a dialog message to prompt the user before another
      Access-Request attempt.

      When used in an Access-Challenge, it MAY indicate a dialog message
      to prompt the user for a response.

      Multiple Reply-Message's MAY be included and if any are displayed,
      they MUST be displayed in the same order as they appear in the
      packet.

   A summary of the Reply-Message Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
   |     Type      |    Length     |  Text ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

   Type

      18 for Reply-Message.

   Length

      >= 3

   Text

      The Text field is one or more octets, and its contents are
      implementation dependent.  It is intended to be human readable,
      and MUST NOT affect operation of the protocol.  It is recommended
      that the message contain UTF-8 encoded 10646 [7] characters.

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5.19.  Callback-Number

   Description

      This Attribute indicates a dialing string to be used for callback.
      It MAY be used in Access-Accept packets.  It MAY be used in an
      Access-Request packet as a hint to the server that a Callback
      service is desired, but the server is not required to honor the
      hint.

   A summary of the Callback-Number Attribute format is shown below.
   The fields are transmitted from left to right.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
   |     Type      |    Length     |  String ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

   Type

      19 for Callback-Number.

   Length

      >= 3

   String

      The String field is one or more octets.  The actual format of the
      information is site or application specific, and a robust
      implementation SHOULD support the field as undistinguished octets.

      The codification of the range of allowed usage of this field is
      outside the scope of this specification.

5.20.  Callback-Id

   Description

      This Attribute indicates the name of a place to be called, to be
      interpreted by the NAS.  It MAY be used in Access-Accept packets.

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   A summary of the Callback-Id Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
   |     Type      |    Length     |  String ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

   Type

      20 for Callback-Id.

   Length

      >= 3

   String

      The String field is one or more octets.  The actual format of the
      information is site or application specific, and a robust
      implementation SHOULD support the field as undistinguished octets.

      The codification of the range of allowed usage of this field is
      outside the scope of this specification.

5.21.  (unassigned)

   Description

      ATTRIBUTE TYPE 21 HAS NOT BEEN ASSIGNED.

5.22.  Framed-Route

   Description

      This Attribute provides routing information to be configured for
      the user on the NAS.  It is used in the Access-Accept packet and
      can appear multiple times.

   A summary of the Framed-Route Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
   |     Type      |    Length     |  Text ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

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   Type

      22 for Framed-Route.

   Length

      >= 3

   Text

      The Text field is one or more octets, and its contents are
      implementation dependent.  It is intended to be human readable and
      MUST NOT affect operation of the protocol.  It is recommended that
      the message contain UTF-8 encoded 10646 [7] characters.

      For IP routes, it SHOULD contain a destination prefix in dotted
      quad form optionally followed by a slash and a decimal length
      specifier stating how many high order bits of the prefix to use.
      That is followed by a space, a gateway address in dotted quad
      form, a space, and one or more metrics separated by spaces.  For
      example, "192.168.1.0/24 192.168.1.1 1 2 -1 3 400". The length
      specifier may be omitted, in which case it defaults to 8 bits for
      class A prefixes, 16 bits for class B prefixes, and 24 bits for
      class C prefixes.  For example, "192.168.1.0 192.168.1.1 1".

      Whenever the gateway address is specified as "0.0.0.0" the IP
      address of the user SHOULD be used as the gateway address.

5.23.  Framed-IPX-Network

   Description

      This Attribute indicates the IPX Network number to be configured
      for the user.  It is used in Access-Accept packets.

   A summary of the Framed-IPX-Network Attribute format is shown below.
   The fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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   Type

      23 for Framed-IPX-Network.

   Length

      6

   Value

      The Value field is four octets.  The value 0xFFFFFFFE indicates
      that the NAS should select an IPX network for the user (e.g.
      assigned from a pool of one or more IPX networks kept by the NAS).
      Other values should be used as the IPX network for the link to the
      user.

5.24.  State

   Description

      This Attribute is available to be sent by the server to the client
      in an Access-Challenge and MUST be sent unmodified from the client
      to the server in the new Access-Request reply to that challenge,
      if any.

      This Attribute is available to be sent by the server to the client
      in an Access-Accept that also includes a Termination-Action
      Attribute with the value of RADIUS-Request.  If the NAS performs
      the Termination-Action by sending a new Access-Request upon
      termination of the current session, it MUST include the State
      attribute unchanged in that Access-Request.

      In either usage, the client MUST NOT interpret the attribute
      locally.  A packet must have only zero or one State Attribute.
      Usage of the State Attribute is implementation dependent.

   A summary of the State Attribute format is shown below.  The fields
   are transmitted from left to right.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
   |     Type      |    Length     |  String ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

   Type

      24 for State.

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   Length

      >= 3

   String

      The String field is one or more octets.  The actual format of the
      information is site or application specific, and a robust
      implementation SHOULD support the field as undistinguished octets.

      The codification of the range of allowed usage of this field is
      outside the scope of this specification.

5.25.  Class

   Description

      This Attribute is available to be sent by the server to the client
      in an Access-Accept and SHOULD be sent unmodified by the client to
      the accounting server as part of the Accounting-Request packet if
      accounting is supported.  The client MUST NOT interpret the
      attribute locally.

   A summary of the Class Attribute format is shown below.  The fields
   are transmitted from left to right.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
   |     Type      |    Length     |  String ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

   Type

      25 for Class.

   Length

      >= 3

   String

      The String field is one or more octets.  The actual format of the
      information is site or application specific, and a robust
      implementation SHOULD support the field as undistinguished octets.

      The codification of the range of allowed usage of this field is
      outside the scope of this specification.

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5.26.  Vendor-Specific

   Description

      This Attribute is available to allow vendors to support their own
      extended Attributes not suitable for general usage.  It MUST not
      affect the operation of the RADIUS protocol.

      Servers not equipped to interpret the vendor-specific information
      sent by a client MUST ignore it (although it may be reported).
      Clients which do not receive desired vendor-specific information
      SHOULD make an attempt to operate without it, although they may do
      so (and report they are doing so) in a degraded mode.

   A summary of the Vendor-Specific Attribute format is shown below.
   The fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |  Length       |            Vendor-Id
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        Vendor-Id (cont)           |  String...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

   Type

      26 for Vendor-Specific.

   Length

      >= 7

   Vendor-Id

      The high-order octet is 0 and the low-order 3 octets are the SMI
      Network Management Private Enterprise Code of the Vendor in
      network byte order, as defined in the "Assigned Numbers" RFC [6].

   String

      The String field is one or more octets.  The actual format of the
      information is site or application specific, and a robust
      implementation SHOULD support the field as undistinguished octets.

      The codification of the range of allowed usage of this field is
      outside the scope of this specification.

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      It SHOULD be encoded as a sequence of vendor type / vendor length
      / value fields, as follows.  The Attribute-Specific field is
      dependent on the vendor's definition of that attribute.  An
      example encoding of the Vendor-Specific attribute using this
      method follows:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |  Length       |            Vendor-Id
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           Vendor-Id (cont)           | Vendor type   | Vendor length |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    Attribute-Specific...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

      Multiple subattributes MAY be encoded within a single Vendor-
      Specific attribute, although they do not have to be.

5.27.  Session-Timeout

   Description

      This Attribute sets the maximum number of seconds of service to be
      provided to the user before termination of the session or prompt.
      This Attribute is available to be sent by the server to the client
      in an Access-Accept or Access-Challenge.

   A summary of the Session-Timeout Attribute format is shown below.
   The fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      27 for Session-Timeout.

   Length

      6

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   Value

      The field is 4 octets, containing a 32-bit unsigned integer with
      the maximum number of seconds this user should be allowed to
      remain connected by the NAS.

5.28.  Idle-Timeout

   Description

      This Attribute sets the maximum number of consecutive seconds of
      idle connection allowed to the user before termination of the
      session or prompt.  This Attribute is available to be sent by the
      server to the client in an Access-Accept or Access-Challenge.

   A summary of the Idle-Timeout Attribute format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      28 for Idle-Timeout.

   Length

      6

   Value

      The field is 4 octets, containing a 32-bit unsigned integer with
      the maximum number of consecutive seconds of idle time this user
      should be permitted before being disconnected by the NAS.

5.29.  Termination-Action

   Description

      This Attribute indicates what action the NAS should take when the
      specified service is completed.  It is only used in Access-Accept
      packets.

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   A summary of the Termination-Action Attribute format is shown below.
   The fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      29 for Termination-Action.

   Length

      6

   Value

      The Value field is four octets.

       0      Default
       1      RADIUS-Request

      If the Value is set to RADIUS-Request, upon termination of the
      specified service the NAS MAY send a new Access-Request to the
      RADIUS server, including the State attribute if any.



(page 50 continued on part 3)

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