draft-park-ipv6-extensions-dns-pnp-00.txt

bind 9.3结合mysql数据库

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  #4. 6DNAC Server processes the DAD/DFQDND NS message and finds 
      that there is no entry for the FQDN in its cache. And,
      creates Cache entry as <FQDN, A> and starts a Registration
      timer with RegistrationWaitTime seconds.

  #5. 6DNAC Client-B finds that the DAD/DFQDND-NS target address is 
      in its unicast address list.  

  #6. It then starts defending DAD by sending NA to all-nodes multicast.

  #7. 6DNAC Server finds that the DAD has failed for 6DNAC Client-A.  
      And, deletes its FQDN Cache entry <FQDN,A>.
      
  #8. 6DNAC Client gets defending DAD-NA and desists from DAD. 
      And also, stops Duplicate FQDN Detection as well.
      At this point the address must be configured using stateful 
      methods and the domain name registration starts with the DAD
      for the newly constructed IPv6 address.
  
  7.3. DNS Zone Suffix Discovery and FQDN Construction
  
  7.3.1. Sending Router Advertisement Messages

  Routers send out Router Advertisement message periodically, 
  or in response to a Router Solicitation. Router should include 
  the DNS Zone Suffix Option in their advertisements. If the DNS
  Zone Suffix changes (similar to Site Renumbering), then it should
  advertise the Old Zone Suffix with zero Valid Lifetime and New
  Zone Suffix with proper non-zero Valid Lifetime.  In any other
  case, a router should not send this option twice in a single
  router advertisement.

  7.3.2. Processing Router Advertisement Messages  

  For each DNS Zone Suffix Option in Router Advertisement,

  a. 6DNAC node stores the Zone Suffix information in its local
     database.  Also, constructs FQDN as per Host Naming Algorithm.

  b. If the node has not configured FQDN yet,

     1. If the node is going to perform DAD for either Site local or 
        Global Address, then it should include FQDN option to perform
        Duplicate FQDN Detection in parallel with DAD.

     2. If the node has already got either Site local or Global 
        address, then it should send out NS with FQDN option and 
        unspecified target address to perform Duplicate FQDN 
        Detection.

  c. If the node has already configured FQDN, and if the 
     advertisement carries two DNS Zone Suffix Options,
     First DNS Zone Suffix should match with the configured FQDN 
     Suffix and its Valid Lifetime must be zero. Second DNS Zone



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     Suffix should have non-zero Valid Lifetime. In this case, the
     node constructs new FQDN based on the new DNS Zone Suffix (from
     second DNS Zone Suffix option), and perform Duplicate FQDN 
     Detection with unspecified target address.  Also, it should
     overwrite the old FQDN with the newly constructed FQDN.
     

  7.3.3. FQDN Lifetime expiry

  6DNAC Server:  
  It should delete the FQDN cache entry and should de-register from
  the DNS Server.

  6DNAC Client:
  It should send update to 6DNAC Server by restarting the Duplicate 
  FQDN Detection. 
  
  7.3.4. Host Naming Algorithm
 
  A node constructs FQDN by combining DNS Zone Suffix and the hostname
  as depicted in the following diagram.

     +------------------+----------------------------------+
     |     Host Name    |          Advertised Suffix       |
     +------------------+----------------------------------+

          <Figure 13: Fully Qualified Domain Name format>

  A node can choose Host Name using any of the following methods:
 
  a. String form of random number generated from the Interface 
     Identifier.
     
  b. List of configured Host Names provided by the administrator.

  
  The number of retries must be specified in this algorithm in 
  case of domain name duplication.
  
    
  7.4. Duplicate Domain Name Detection
  
  The procedure for detecting duplicated FQDNs uses Neighbor
  Solicitation and Advertisement messages as described below.

  If a duplicate FQDN is detected during the procedure, the
  FQDN cannot be assigned to the node.

  An FQDN on which the DFQDND Procedure is applied is said 
  to be tentative until the procedure has completed successfully.  
  A tentative FQDN is not considered "assigned to the node" in the 
  traditional sense.  That is, the node must accept Neighbor 
  Advertisement message containing the tentative FQDN in the FQDN 
  Option.


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  It should also be noted that DFQDN must be performed prior to 
  registering with DNS Server to prevent multiple nodes from using 
  the same FQDN simultaneously. All the Duplicate Address Detection 
  Neighbor Solicitation messages must carry Source Link Layer Address 
  Option as specified in NDP [2461]. 

  The detection of duplicate FQDN can be achieved through one of the
  following three types of procedures.
  
  1. DAD with All Nodes Multicast Address
  2. DAD with Router Alert Option for 6DNAC.
  3. Explicit Detection of Duplicate Domain Name
   
  Even though three solutions are listed, authors prefer only one 
  procedure to be followed in future based on further analysis and
  comments received from others. 
  
  7.4.1. DAD with All Nodes Multicast Address
  
  7.4.1.1. Sending Neighbor Solicitation Messages

  6DNAC Client sends Neighbor Solicitation Messages as part
  of Duplicate Address Detection SLAAC [2462] with the following 
  extra information and modifications:

  a. Include FQDN Option in the DAD Neighbor Solicitation Message
  b. Destination Address is set to All Nodes Multicast Address

  There may be a case where DAD has succeeded but DFQDND is in Retry 
  Mode. In such case, the Neighbor Solicitation must carry unspecified 
  address in the ICMP target address field and new domain name in FQDN
  option to re-try the registration of the domain name.

  7.4.1.2. Processing Neighbor Solicitation Messages

  6DNAC Clients must ignore the FQDN option found in any of the
  neighbor solicitation messages.

  6DNAC Server processes FQDN Option found in the Duplicate Address 
  Detection Neighbor Solicitation Messages as described below:

  Lookup FQDN Cache for the domain name in FQDN Option.

  If the entry exists and 
   i. Link Layer Address matches with SLLA option, this is the case, 
      where node has changed its IPv6 address or updating the valid 
      life time. 6DNAC Server updates its cache and also updates DNS
      Server using DDNS-UPDATE. If there is no change in IPv6 address
      or life time then no updates are sent to the DNS server. 

  ii. Link Layer Address differs with SLLA option, defend the duplicate 
      FQDN Detection by sending Neighbor Advertisement Message as 
      described in $7.4.1.3$.



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  else,
    Lookup FQDN Cache for the Link Layer Address in SLLA Option.

    If the entry exists, update the FQDN Cache and update DNS Server 
    using DDNS-UPDATE. This is the case, where node has changed its
    domain name (similar to Site Re-numbering).

    If then entry does not exists, then it means that this is the new 
    registration. It must create a cache entry and start Registration    
    
    timer with RegistrationWaitTime. At the expiry of the Registration
    timer, it should update DNS Server with DDNS-UPDATE.

  7.4.1.3. Sending Neighbor Advertisement Messages

  6DNAC Server sends Neighbor Advertisement Messages as part
  of Duplicate Address Detection SLAAC [2462] with the FQDN Option 
  in Neighbor Advertisement message to defend duplicate FQDN 
  detection.

  There may be the case where defending of duplicate address detection 
  is not required but defending of FQDN is required.  In such instance, 
  the defending Neighbor Advertisement must carry FQDN and unspecified
  address in the ICMP target address field.

  7.4.1.4. Processing Neighbor Advertisement Messages

  6DNAC Server must ignore the any FQDN option found any of 
  the neighbor advertisement messages.  If the Neighbor Advertisement
  is a DAD defending, then it must delete its FQDN Cache entry created 
  on the reception of DAD Neighbor Solicitation message.

  When 6DNAC Clients gets the duplicate address detection neighbor
  advertisement messages with FQDN option set it means that its
  duplicate FQDN detection failed and enters Retry Mode.

  7.4.1.5. Pros and Cons
  
  The advantage of this procedure is that it does not need any 
  extension header options to be included. The disadvantage of this 
  procedure is that, it needs change in the existing DAD procedure.
  The change is only that the DAD neighbor solicitations are to be 
  addressed to all nodes multicast address instead of solicited 
  node multicast address. The another disadvantage is that, it needs 
  the existence of Duplicate Address Detection Procedure to 
  perform duplicate FQDN detection. 
  
  7.4.2. DAD with Router Alert Option for 6DNAC

  7.4.2.1. Sending Neighbor Solicitation Messages

  6DNAC Client sends Neighbor Solicitation Messages as part
  of Duplicate Address Detection SLAAC [2462] with the following 
  extra information:


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  a. Include Hop-by-Hop extension Header with Router Alert Option
     for 6DNAC as described in IPv6 Router Alert Option[2711].

  b. Include FQDN Option in the DAD Neighbor Solicitation Message

  7.4.2.2. Processing Neighbor Solicitation Messages

  This is same as described in $7.4.1.2$. 

  7.4.2.3. Sending Neighbor Advertisement Messages

  This is same as described in $7.4.1.3$. 

  7.4.2.4. Processing Neighbor Advertisement Messages

  This is same as described in $7.4.1.4$.

  7.4.2.5. Pros and Cons

  The advantage of this procedure is that it does not disturb
  the existing implementation and their way of processing the 
  packets.  The disadvantage is that, it needs the existence 
  of Duplicate Address Detection Procedure to perform duplicate 
  FQDN detection. Another disadvantage is that this procedure 
  requires 6DNAC Server functionality to be implemented on Router.
  However, in this case 6DNAC Server can serve multiple links.
  
  7.4.3. Explicit Detection of Duplicate Domain Name

  In this procedure Duplicate FQDN Detection starts after completion
  of successful Site local or Global Address configuration.
  
  7.4.3.1. Sending Neighbor Solicitation Messages

  6DNAC Client sends Neighbor Solicitation Messages as part
  of Duplicate FQDN Detection with the following information:

  a. Include FQDN Option in the Neighbor Solicitation Message

  b. Destination Address is set to All Nodes Multicast Address
     or uses Router Alert Option for 6DNAC, when 6DNAC Server is 
     implemented on router.

  c. Target Address is set to Unspecified Address

  d. Other fields are set as per DAD SLAAC [2462].

  7.4.3.2. Processing Neighbor Solicitation Messages

  This is same as described in $7.4.1.2$.






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  7.4.3.3. Sending Neighbor Advertisement Messages

  This is same as described in $7.4.1.3$.

  7.4.3.4. Processing Neighbor Advertisement Messages

  This is same as de