Modification to Default Values of SOL_MAX_RT and INF_MAX_RT
draft-ietf-dhc-dhcpv6-solmaxrt-update-04

#x27;s DUID, a Client
   Identifier option with the client's DUID and (optionally)

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   SOL_MAX_RT and/or INF_MAX_RT options.

   Add text to the end of section 14, clarifying client behavior while
   waiting for a response from a server:

   NEW:

   A client is not expected to listen for a response during the entire
   period between transmission of Solicit or Information-Request
   messages.

7.  DHCPv6 Client Behavior

   A DHCPv6 client MUST include the SOL_MAX_RT option code in any Option
   Request option [RFC3315] it sends as required by RC 3315.

   A DHCPv6 client MUST include the INF_MAX_RT option code in any Option
   Request option [RFC3315] it sends as required by RFC 3315.

   A DHCPv6 client MUST silently ignore any SOL_MAX_RT or INF_MAX_RT
   option values that are less than 60 or more than 86400.

   If a DHCPv6 client receives a message containing a SOL_MAX_RT option
   containing a valid value for SOL_MAX_RT, the client MUST set its
   internal SOL_MAX_RT parameter to the value contained in the
   SOL_MAX_RT option.  This value of SOL_MAX_RT is then used by the
   retransmission mechanism defined in sections 17.1.2 and 14 of RFC
   3315 [RFC3315].

   If a DHCPv6 client receives a message containing a INF_MAX_RT option
   containing a valid value for INF_MAX_RT, the client MUST set its
   internal INF_MAX_RT parameter to the value contained in the
   INF_MAX_RT option.  This value of INF_MAX_RT is then used by the
   retransmission mechanism defined in sections 18.1.5 and 14 of RFC
   3315 [RFC3315].

8.  DHCPv6 Server Behavior

   Sections 17.2.2 and 18.2 of [RFC3315] govern server operation in
   regards to option assignment.  As a convenience to the reader, we

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   mention here that the server will send option SOL_MAX_RT and
   INF_MAX_RT only if configured with specific values for them and the
   client requested those options using Option Request Option.

   The DHCPv6 server MAY include the SOL_MAX_RT option in any response
   it sends to a client that has included the SOL_MAX_RT option code in
   an Option Request option.  The SOL_MAX_RT option is sent in the main
   body of the message to client, not as a encapsulated option in, e.g.,
   an IA_NA, IA_TA [RFC3315] or IA_PD [RFC3633] option.

   The DHCPv6 server MAY include the INF_MAX_RT option in any response
   it sends to a client that has included the INF_MAX_RT option code in
   an Option Request option.  The INF_MAX_RT option is sent in the main
   body of the message to client, not as a encapsulated option in, e.g.,
   an IA_NA, IA_TA [RFC3315] or IA_PD [RFC3633] option.

9.  DHCPv6 Relay Agent Behavior Text

   There are no additional requirements for relays.

10.  Security Considerations

   This document introduces one security consideration beyond those
   described in RFC 3315 [RFC3315].  A malicious DHCPv6 server might
   cause a client to set its SOL_MAX_RT and INF_MAX_RT parameters to an
   arbitrarily high value with the SOL_MAX_RT and INF_MAX_RT options,
   which may cause an undue delay in a client completing its DHCPv6
   protocol transaction in the case no other valid response is
   received..  Assuming the client also receives a response from a valid
   DHCPv6 server, large values for SOL_MAX_RT and INF_MAX_RT will not
   have any effect.

11.  Acknowledgments

   Tomek Mrugalski edited the text for compliance with draft-ietf-dhc-
   option-guidelines [I-D.ietf-dhc-option-guidelines] and added
   important details to the Security Considerations section.

12.  IANA Considerations

   IANA is requested to assign one option code each for
   OPTION_SOL_MAX_RT and OPTION_INF_MAX_RT from the "DHCP Option Codes"
   table of the Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
   Registry.

13.  References

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13.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3315]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
              and M. Carney, "Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6)", RFC 3315, July 2003.

13.2.  Informative References

   [I-D.ietf-dhc-option-guidelines]
              Hankins, D., Mrugalski, T., Siodelski, M., Jiang, S., and
              S. Krishnan, "Guidelines for Creating New DHCPv6 Options",
              draft-ietf-dhc-option-guidelines-13 (work in progress),
              July 2013.

   [RFC3633]  Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
              Host Configuration Protocol (DHCP) version 6", RFC 3633,
              December 2003.

Author's Address

   Ralph Droms
   Cisco Systems
   1414 Massachusetts Avenue
   Boxborough, MA  01719
   USA

   Phone: +1 978 936 1674
   Email: rdroms@cisco.com

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