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IPv6 Clients  Autoconfiguration  The whole process In-Depth fully explained!   Version 2.0© 2011 Fred Bovy.               ...
Presentation Objectives           This presentation gives an in-depth explanation of the IPv6           Autoconfiguration ...
About the Author           Fred Bovy              §  15 years experience in IPv6                    –  IPv6 Forum Certifi...
Introduction to Autoconfiguration           IPv6 Autoconfiguration© 2011 Fred Bovy.                             IPv6AutoCo...
What is Autoconfiguration ?      §  With Autoconfiguration, a network node can      configure itself completely and modif...
Autoconfiguration (SLAAC) on Linux!      Autoconfiguration is Enabled by default on      most platforms but Linux !      F...
Autoconfig Addresses in Tentative Mode  Autoconfiguration First Step is the Tentative Mode to verify the IPv6  Addresses w...
Autoconfig Address is in Preferred state       n  The « NORMAL » state for an address in production.       n  The addres...
Autoconfig Address is in Deprecated state       The Address was not refreshed by a RA or DHCPv6 for Preferred timer…      ...
Autoconfig Address is in Valid state       The address can be used to send and received unicast traffic       Valid state ...
Autoconfig Address is in Invalid State       The address cannot be used to send or receive traffic       The address reach...
IPv6 Interface is going up           IPv6 Autoconfiguration© 2011 Fred Bovy.                      IPv6AutoConfig—2-12
Client initializes the Link-Local Address                    Derive the link-local                         address        ...
1. IPv6 Interface is going up           1.  Initialize and check the Link-Local Address           2.  Send a Router Solici...
Initialization of the Link-Local Address         Workstation picks up a link-local address             §  i.e. fe80::202:...
Ubuntu performing DAD (NS) CapturedIPv6 Neighbor SolicitationIPv6 Router Solicitationmessage to the All-Routersff02::2IPv6...
Client Send Request and get Autoconf parameters                    Derive the link-local                         address  ...
2. IPv6 Intf is Going Up!      1.  Link-Local Address initialized and unique !      2.  Send a Router Solicitation (RS) me...
2. Clients request Autoconfig Information              The client issues a Router Solicitation (RS) using its link-local a...
To Accept RA on Linux clients           For Linux, it must be configured with sysctl command or             editing the /e...
ISP 6RD RG RARouter Solicitation andRouter AdvertisementRouter Advertisementsent to the All-IPv6 Nodes multicastff02::1Rou...
If no RA Received, clients run DHCPv6          DHCPv6                                                                     ...
DO NOT SUPPRESS the RA on LAN intf to force DHCPv6       By default the RA are enabled on a LAN interface and disabled on ...
Client is looping on the prefixes lists        to autoconfigure new Addresses                             A               ...
IPv6 Interface is going Up!           1.  Link-Local Address Validated, IPv6 Intf is UP!           2.  A Router Solicitati...
Router Advertisements (RA) information           §  The Router is a candidate for default Route?                    The L...
RA on Cisco Router - show ipv6 routers hote#show ipv6 routers Router FE80::2038:148E:B9DF:FD6D on FastEthernet0/0, last   ...
Client process the Optional RA Prefix(es) List           In each RA there may be a list of Prefixes which can             ...
Accept Prefixes from RA on Linux clients© 2011 Fred Bovy.                               IPv6AutoConfig—2-29
The Client processes each Prefix of the List        The Prefix is selected for SLAAC if both On-Link and Autonomous bits  ...
Client checks if DHCPv6 can be used                    Derive the link-local                         address              ...
IPv6 Interface is Going Up!           1.  Initialize and validate the Link-Local Address. IPv6 Intf Up!           2.  Rout...
Clients check if DHCPv6 MUST be used       In each RA there are 2 flags to advertize the use of DHCPv6!       Managed Addr...
IPv6 Autoconfiguration Modes            Stateless Address Autoconfiguration            §  NO DHCPv6, all the configuratio...
Stateless Address AutoConfig Signalisation       IPv6 routers signal the use of DHCPv6, if both       bit are not cleared ...
Stateless Address AutoConfiguration       n  RFC 4862, IPv6 Stateless Address Autoconfiguration           n RS/RA To req...
Stateful DHCPv6 Autoconfig Signalisation       IPv6 routers signal the use of DHCPv6. Not M       and O bits must be set i...
Statefull DHCPv6 Autoconfiguration Address and Other parameters are configured from DHCPv6                      DHCPv6 wit...
Stateless DHCPv6 Autoconfig Signalisation           IPv6 Routers signal the DHCPv6 utilization              §  M bit = 0 ...
Stateless DHCPv6 AutoconfigurationAddressconfigurationfrom the prefixreceived in theRA (SLAAC)Other parametersare given by...
DHCP Prefix Delegation        DHCPv6 PD Server allocates a block of        addresses for the DHCPv6-PD Client        The b...
DHCPv6-PD Client and DHCPv6 Stateless Server                                                                              ...
6RD Service Providers RG Autoconfig                                  6rd           6rd                    IPv4 + IPv6     ...
Autoconfigured Address Refreshment           IPv6 Autoconfiguration© 2011 Fred Bovy.                              IPv6Auto...
Remember the Preferred state !         n  This is the « NORMAL » state for an address in production.         Each address...
Autoconfigured addresses have a finiteValid and Preferred Lifetime           When the Interface has been started and is us...
Refreshing the SLAAC Addresses Timers           •  An address which has been derived from a RA must              be refres...
Update the Address Preferred and Valid Timers              The preferred lifetime of each address is reset to the         ...
SLAAC Prefix Refreshed and Timers Updated by RA21001900                                                                   ...
Theses Timers are also in DHCPv6 Addresses          Addresses are coded as DHCPv6 Options          •  IA Address Option (I...
Address Refreshed by DHCPv6-PD Renew© 2011 Fred Bovy.                           IPv6AutoConfig—2-51
Renumbering           IPv6 Autoconfiguration© 2011 Fred Bovy.                   IPv6AutoConfig—2-52
Principle of Renumbering for IPv6           Renumbering can be performed thanks to RA or DHCPv6           1.  Old prefix i...
Renumbering Scenario using RA       Routers Configuration                                                               Va...
Mobile IPv6: keep your home address everywhere              you go, keep always online and only logout when              y...
Mobile IPv6 for dummies…           Without Mobile IPv6, everytime you visit a new access           network, your network a...
Why MIPv6 never restart any session?               §  The MN can roam from subnet to subnet getting a new IPv6 address fo...
Mobile IPv6 is supported on Linux and Free BSD               §  For MAC OS X check KAME Free BSD                    –  KA...
Most Important Terminology           Home Agent           The router which forward the traffic to the Mobile Node (MN)    ...
Mobile Node visits a new access network              §  MN must acquire its Care-of-Address (CoA)              §  Autoco...
Mobile Node (MN) initializes its new location               §  The Mobile Node (MN) registers its CoA with the Home Agent...
Why the Applications don’t need to restart           their Transport Connection (i.e TCP)?                                ...
Can we build a direct tunnel to bypass the HA?             1.  The Corresponding Node (CN) must support Mobile IPv6 with  ...
Why the CN Application receives packets of the MN           originated from the MN Home Network Address?                  ...
Why the MN Application receives a packet with          the Home Network Addr as the dst Addr?                     Mobile N...
Mobile IPv6 Applications               § Proxy Mobile IPv6 (PMIPv6) for LTE and 4G               § Mobile Router or Nemo...
Proxy Mobile IPv6 introduced with LTE                                                                                     ...
Proxy MIPv6 converts ND requests to MIPv6 Signaling1.          The MN sends a RS (Router Solicitation) to the MAG.2.      ...
The Mobile Router: Nemo              §  Mobile Router can receive a block of addresses from DHCPv6-PD              §  Th...
Mobile Ad Hoc Networking: Manet      With MANET, the nodes discover automatically configure their      neighbors and build...
Wireless Sensors Networks (6LoWPAN)The Network of Sensors can be built dynamicallyusing Dynamic MANET On-demand for6LoWPAN...
Thank you for attending!This concludes IPv6 Autoconfiguration In-depth PresentationFred BovyIPv6 Forum Gold Certified Engi...
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IPv6 Autoconfig

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IPv6 Autoconfig full process from initial configuration of IPV6 Node. Refreshment of IPv6 Addresses using RA or DHCPv6. How to keep your home config everywhere you go and only logout when you want to, not when you move to a new access point.

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Transcript of "IPv6 Autoconfig"

  1. 1. IPv6 Clients Autoconfiguration The whole process In-Depth fully explained! Version 2.0© 2011 Fred Bovy. IPv6AutoConfig—2-1
  2. 2. Presentation Objectives This presentation gives an in-depth explanation of the IPv6 Autoconfiguration process. It covers all the possible combinations to configure and to maintain automatically the IPv6 nodes using all the possible options currently available. This presentation focuses on IPv6 Autoconfiguration but it also introduces the Mobile IPv6 based applications. At the end of the presentation you will fully understand how the IPv6 nodes initially get configured and how the network configuration may be changed over time if needed. You will also understand the benefits of running Mobile IPv6. And you will deserve a good coffee break!© 2011 Fred Bovy. IPv6AutoConfig—2-2
  3. 3. About the Author Fred Bovy §  15 years experience in IPv6 –  IPv6 Forum Certified Gold Engineer –  IPv6 Forum Certified Gold Trainer §  20+ years experience with CISCO, TCP/IP –  15 years CCIE #3013 (it was only R&S in 1997!) –  18 years CCSI #33517 since 1994 (it was #95003) –  7 years Cisco IOS IPv6 Software Engineer (NSSTG Group) –  3 years Cisco Network Consultant (CA Group) §  12+ years experience in MPLS Meet me on: –  Twitter: FredBovy –  Skype: FredericBovy –  Blogs: http://www.fredbovy.com/Go46/ –  LinkedIn, owner of 3 IPv6 Groups –  Email me: fred@fredbovy.com© 2011 Fred Bovy. IPv6AutoConfig—2-3
  4. 4. Introduction to Autoconfiguration IPv6 Autoconfiguration© 2011 Fred Bovy. IPv6AutoConfig—2-4
  5. 5. What is Autoconfiguration ? §  With Autoconfiguration, a network node can configure itself completely and modify its configuration anytime needed. Network Addresses, default route, DNS and Others Servers addresses, domain name, Dynamic DNS Updates §  How Autoconfiguration is used: For Offices or Campuses: -  Renumbering if a new prefix must be used for a site or a company -  For privacy, the Interface ID can be changed with a random value every day -  With Mobile IPv6 enabled, support the Mobile users. They keep using their office home addresses while they are roaming. Roaming devices without Mobile IPv6 -  Autoconfigured is used to get addresses for each visited access network -  Application must be restarted each time as sockets are differents -  This is how MOST devices are currently operating ! Mobile IPv6: Mobile Routers (NEMO), MANET, Sensors (6LowPAN) -  The home Address is the only address known by the end-user Application -  A new Address (COA) acquired by Autoconfig is used for each visited network (Wifi, 3G) -  Because the home address is the same, the same socket is used, there is no interruption, no need to restart the applications© 2011 Fred Bovy. IPv6AutoConfig—2-5
  6. 6. Autoconfiguration (SLAAC) on Linux! Autoconfiguration is Enabled by default on most platforms but Linux ! For Linux use sysctl -w or add in the /etc/ sysctl.conf the following configuration: To Enable Autoconfig use: This is only about Stateless Address Autoconfiguration (SLAAC) and has nothing to do with Mobile IPv6. We will introduce Mobile IPv6 later in this presentation© 2011 Fred Bovy. IPv6AutoConfig—2-6
  7. 7. Autoconfig Addresses in Tentative Mode Autoconfiguration First Step is the Tentative Mode to verify the IPv6 Addresses which are configured or could be configured on the interface IPV6 INTERFACE IS GOING UP… §  First, the Link local address is generated and tested to enable the interface for IPv6 §  The Link Local address is verified with Duplicate Address Detection (DAD) §  The Link-Local address MUST be valid or Autoconfig exits and the Interface is disabled for IPv6 §  Once the Link-Local passed DAD, the IPv6 Interface is Up and other addresses are also generated from the RA or allocated by DHCPv6 and validated by DAD Valid Tentative Preferred Deprecated Invalid Preferred Lifetime Valid Lifetime© 2011 Fred Bovy. IPv6AutoConfig—2-7
  8. 8. Autoconfig Address is in Preferred state n  The « NORMAL » state for an address in production. n  The address verified by DAD can be used to send and receive unicast traffic. n  The address can be used for new connections or by existing one n  The Preferred Lifetime is determined by the field Preferred Lifetime included in the RA Prefix Information or the Preferred-Lifetime Option in the DHCPv6 As long as the derived Address is refreshed with RA Prefixes or the allocated address is reniewed by DHCPv6, the address state will remain Preferred! Valid Tentative Preferred Deprecated Invalid Preferred Lifetime Valid Lifetime© 2011 Fred Bovy. IPv6AutoConfig—2-8
  9. 9. Autoconfig Address is in Deprecated state The Address was not refreshed by a RA or DHCPv6 for Preferred timer… n  Can be used for Renumbering, during the transition to a NEW prefix n  New connection SHOULD not use this address n  Existing communications SHOULD still be able to use this address as source. « An implementation MAY prevent any new communication from using a deprecated address, but system management MUST have the ability to disable such a facility, and the facility MUST be disabled by default. » RFC4862! Valid Tentative Preferred Deprecated Invalid Preferred Lifetime Valid Lifetime© 2011 Fred Bovy. IPv6AutoConfig—2-9
  10. 10. Autoconfig Address is in Valid state The address can be used to send and received unicast traffic Valid state = Preferred + Deprecated The Valid Lifetime is determined by the field Valid Lifetime included in the RA Prefix Information or the Valid-Lifetime Option in the DHCPv6 IA Address Valid Tentative Preferred Deprecated Invalid Preferred Lifetime Valid Lifetime© 2011 Fred Bovy. IPv6AutoConfig—2-10
  11. 11. Autoconfig Address is in Invalid State The address cannot be used to send or receive traffic The address reaches the Invalid state when the Valid Lifetime has expired « An address (and its association with an interface) becomes invalid when its valid lifetime expires. An invalid address MUST NOT be used as a source address in outgoing communications and MUST NOT be recognized as a destination on a receiving interface. » RFC4862! Valid Tentative Preferred Deprecated Invalid Preferred Lifetime Valid Lifetime© 2011 Fred Bovy. IPv6AutoConfig—2-11
  12. 12. IPv6 Interface is going up IPv6 Autoconfiguration© 2011 Fred Bovy. IPv6AutoConfig—2-12
  13. 13. Client initializes the Link-Local Address Derive the link-local address Set Hop Limit, FE80::[Interface ID] Reachable Time, Retrans Timer, MTU Send multicast NS. Destination address Prefix Yes derived from the link- Information A local present ? No Yes B NA received ? Stop Managed Address Yes No Configuration Flag = 1 ? Initialize the link-local No Other Yes Send RS Configuration Use DHCPv6 Flag = 1 ? No No RA Received ? Use DHCPv6 Stop Yes© 2011 Fred Bovy. IPv6AutoConfig—2-13
  14. 14. 1. IPv6 Interface is going up 1.  Initialize and check the Link-Local Address 2.  Send a Router Solicitation (RS) message to get the Autoconfiguration info from the Router Advertizements (RA) 3.  Initialize and validate default Parameters and other Addresses derived from the Prefixes learned from the Router Advertizement (RAs) 4.  Check if DHCPv6 must be used for Addresses ? Other configurations ? fe80::202:b3ff:fe1e:8329 To A’s Solicited node address FF02::1:FF1E:8329© 2011 Fred Bovy. IPv6AutoConfig—2-14
  15. 15. Initialization of the Link-Local Address Workstation picks up a link-local address §  i.e. fe80::202:b3ff:fe1e:8329 EUI-64 §  Using prefix fe80::/10 and build the 64 bit Interface ID from EUI-64 format §  May be generated Cryptographically if SeND CGA is used (RFC3972) Workstation performs Duplicate Address Detection (DAD) §  Sends NS to its own Neighbor Solicited Node Multicast Address ! –  FF02::1:FF00:0/104 + last 24 bits = ff02::1:ff1:8329 §  Expect no answer or the address is a duplicated (DUP) IF DAD Fails for the the Link-Local address the IPv6 Intf is disabled ! 3 attempts if CGA(RFC3972)© 2011 Fred Bovy. IPv6AutoConfig—2-15
  16. 16. Ubuntu performing DAD (NS) CapturedIPv6 Neighbor SolicitationIPv6 Router Solicitationmessage to the All-Routersff02::2IPv6 Source address is :: Neighbor SolicitationDst address is the solicitednode multicast address:ff02::1:ff30:3386 © 2011 Fred Bovy. IPv6AutoConfig—2-16
  17. 17. Client Send Request and get Autoconf parameters Derive the link-local address Set Hop Limit, FE80::[Interface ID] Reachable Time, Retrans Timer, MTU Send multicast NS. Destination address Prefix Yes derived from the link- Information A local present ? No Yes B NA received ? Stop Managed Address Yes No Configuration Flag = 1 ? Initialize the link-local No Other Yes Send RS Configuration Use DHCPv6 Flag = 1 ? No No RA Received ? Use DHCPv6 Stop Yes© 2011 Fred Bovy. IPv6AutoConfig—2-17
  18. 18. 2. IPv6 Intf is Going Up! 1.  Link-Local Address initialized and unique ! 2.  Send a Router Solicitation (RS) message to get the Autoconfiguration info from the Router Advertizements (RA) 3.  Initialize and validate default Parameters and other Addresses derived from the Prefixes learned from the Router Advertizement (RAs) 4.  if Check DHCPv6 must be used for Addresses ? Other conffigurations ?© 2011 Fred Bovy. IPv6AutoConfig—2-18
  19. 19. 2. Clients request Autoconfig Information The client issues a Router Solicitation (RS) using its link-local as source Address to the all-routers multicast destination address to request all the parameters needed for autoconfiguration: §  The default Hop Limit, the Link MTU, a default route… §  The Prefixes to used for autoconfiguration §  DHCPv6 must be used and what for? Addresses or Other Configurations? If NO Response to the RS, then try a DHCPv6 SolicitNo Router and EXIT Autoconfig!!! All-Routers: FF02::2 © 2011 Fred Bovy. IPv6AutoConfig—2-19
  20. 20. To Accept RA on Linux clients For Linux, it must be configured with sysctl command or editing the /etc/sysctl.conf file. Use sysctl -w or add in the /etc/sysctl.conf the following config: To Accept the RA use:© 2011 Fred Bovy. IPv6AutoConfig—2-20
  21. 21. ISP 6RD RG RARouter Solicitation andRouter AdvertisementRouter Advertisementsent to the All-IPv6 Nodes multicastff02::1Router Lifetime: 1800 secondesDon’t modify the ReachableTimer and the Retrans timerPrefix Option:2a01:e35:2f26:d340::/64On-Link Bit Flag SetAutonomous Bit Flag SetValid Lifetime: 86400 secPreferred Lifetime: 86400 sec DNS Servers Option: 2a01:e00::1 2a01:e00::2 MTU Option: 1480 bytes Source Link Layer Address Option f4:ca:e5:44:10:ef © 2011 Fred Bovy. IPv6AutoConfig—2-21
  22. 22. If no RA Received, clients run DHCPv6 DHCPv6 DHCPv6 Client Server DHCPv6 Relay! Relay-Forward Solicit to All_DHCP_Servers (FF05::1:3) Dst:All_DHCP_Relay_Agents_and_Servers (FF02::1:2) Relay- Advertize replyRequestDst: Server Dst:All_DHCP_Relay_Agents_and_Servers(FF02::1:2) Relay-ForwardSrc: Client Link-local address to All_DHCP_Servers (FF05::1:3) Relay-reply Dst: Client Link-local address Reply Src: Server Link-local address If no RA Received, Autoconfiguration ends here !© 2011 Fred Bovy. IPv6AutoConfig—2-22
  23. 23. DO NOT SUPPRESS the RA on LAN intf to force DHCPv6 By default the RA are enabled on a LAN interface and disabled on a Serial Point to Point. RAs are very useful to provide many other important IPv6 parameters like a default route, link MTU, the default Hop-Limit or the Neighbor Unreachability (NUD) parameters and more. If no RA is received, the client tries DHCPv6 and Exits Autoconfiguration! For the clients to use DHCPv6: Set the Managed Addr Config and Other Config flags. IPv6 is not IPv4 Suppressing the RA will not convert IPv6 to IPv4 DHCPv6 cannot provide a default route !© 2011 Fred Bovy. IPv6AutoConfig—2-23
  24. 24. Client is looping on the prefixes lists to autoconfigure new Addresses A Yes Do not initialize NA the stateless Take the first Received ? address prefix information No Initialise the Yes Stateless On-Link Flag Add the prefix to address =1? the list No No No Autonomous Other prefixes to process B Flag = 1 ? Yes Yes Derive the Stateless Prefixe:[interface ID] Go to next prefix Send NS to the derived address© 2011 Fred Bovy. IPv6AutoConfig—2-24
  25. 25. IPv6 Interface is going Up! 1.  Link-Local Address Validated, IPv6 Intf is UP! 2.  A Router Solicitation (RS) message was sent and a Router Advertizements (RA) was Received 3.  Initialize and validate the default Parameters and other Addresses derived from the Prefixes learned from the Router Advertizement (RAs) 4.  Check if DHCPv6 must be used for Addresses ? Other configurations ?© 2011 Fred Bovy. IPv6AutoConfig—2-25
  26. 26. Router Advertisements (RA) information §  The Router is a candidate for default Route? The Lifetime timers is how long a Router will remain a valid next hop without any refresh. If Lifetime = 0, the router cannot be used as a default route if Lifetime > 0, the Link-local IPv6 Address must be used as a default next hop. The RA also contains a Router Preference: Low, Medium or High. The router MAC Address is also provided in the SLLA Option. §  Other Important Configuration: Hop Limit and MTU for the Link Reachable Timer and Retransmit interval used by NUD DNS Servers Addresses in the DNS Option (RFC6106) A List of zero or more prefix(es) §  Should we also use of DHCPv6 for more Autoconfig? Managed and Other Config Flags Warning: RFC6104. Rogue RA !!!© 2011 Fred Bovy. IPv6AutoConfig—2-26
  27. 27. RA on Cisco Router - show ipv6 routers hote#show ipv6 routers Router FE80::2038:148E:B9DF:FD6D on FastEthernet0/0, last update 2 min Hops 64, Lifetime 1800 sec, AddrFlag=0, OtherFlag=0, MTU=1500 HomeAgentFlag=0, Preference=Medium Reachable time 0 (unspecified), Retransmit time 0 (unspecified) Prefix 2001::/64 onlink autoconfig Valid lifetime 2592000, preferred lifetime 604800 IMPORTANT REMARKS: The Router Lifetime applies only to the routers usefulness as a default router; it does not apply to information contained in other message fields or options. Options that need time limits for their information include their own lifetime fields. A router which can’t be used as a default router or shutting down sends a RA with Lifetime=0 (0) Unspecified does not mean that the parameter must set to zero but it means « DO NOT CHANGE » whatever value which is preconfigured on the node© 2011 Fred Bovy. IPv6AutoConfig—2-27
  28. 28. Client process the Optional RA Prefix(es) List In each RA there may be a list of Prefixes which can be used by SLAAC Each Prefix comes with: §  The Length of the Prefix §  2 bits or Flags: the On-Link bit and the Autonomous bit –  Both flags MUST be SET for the Prefix to be used by SLAAC A full Stateless 128 bits address can be derived from the prefix adding an Interface ID –  The 64 bits Interface ID can be built: - From the MAC Address: EUI-64 format or - With a Random Number if Privacy Extension is configured (RFC4941) §  2 Timers: the Preferred Timers and the Valid Timers. –  This is how long the addresses derived from the RA advertized prefix if learned from SLAAC will remain in the Preferred and in the Valid States. These timers are also managed when the addresses are allocated by a DHCPv6 Stateful Server. –  The Timers can be reset by the periodic RA, in this case, the unsolicited RA transmission interval must be set to refresh the SLAAC derived addreses before they get deprecated or invalid. The Timers can also be refreshed by DHCPv6 protocol. –  Statically configured IPv6 addresses have Infinite Preferred and Valid Timers.© 2011 Fred Bovy. IPv6AutoConfig—2-28
  29. 29. Accept Prefixes from RA on Linux clients© 2011 Fred Bovy. IPv6AutoConfig—2-29
  30. 30. The Client processes each Prefix of the List The Prefix is selected for SLAAC if both On-Link and Autonomous bits are set, then Use EUI-64: Interface ID is derived from the MAC Address 00 90 59 02 E0 F9O 00 90 59 FF FE 02 E0 F9 Mac Address 48 bit X=1 UniqueR 000000X0 X=0 Not Unique Use Privacy Extension (RFC4941): Interface ID is selected randomly On Windows netsh interface ipv6 set privacy=enabled On Mac OS X sysctl net.inet6.ip6.use_tempaddr=1 On Linux sysctl net.ip6.conf.if.use_tempaddr=2© 2011 Fred Bovy. IPv6AutoConfig—2-30
  31. 31. Client checks if DHCPv6 can be used Derive the link-local address Set Hop Limit, FE80::[Interface ID] Reachable Time, Retrans Timer, MTU Send multicast NS. Destination address Prefix Yes derived from the link- Information A local present ? No Yes B NA received ? Stop Managed Address Yes No Configuration Flag = 1 ? Initialize the link-local No Other Yes Send RS Configuration Use DHCPv6 Flag = 1 ? No No RA Received ? Use DHCPv6 Stop Yes© 2011 Fred Bovy. IPv6AutoConfig—2-31
  32. 32. IPv6 Interface is Going Up! 1.  Initialize and validate the Link-Local Address. IPv6 Intf Up! 2.  Router Solicitation (RS) message Sent and the Router Advertizements (RA) received 3.  Initialize and validate default Parameters and other Addresses derived from the Prefixes learned from the Router Advertizement (RAs) 4.  Check if DHCPv6 must be used for Addresses ? Other configurations ?© 2011 Fred Bovy. IPv6AutoConfig—2-32
  33. 33. Clients check if DHCPv6 MUST be used In each RA there are 2 flags to advertize the use of DHCPv6! Managed Address Configuration Flag The Managed Address or M flag tells the clients to use DHCPv6 to configure IPv6 Address(es) Actually when the M bit is set, DHCPv6 is used to request all the available DHCPv6 configuration other information and the O is redundant Cisco Interface config « ipv6 nd managed-config-flag » Other Configuration Flag The Other or O flag tells the clients to use DHCPv6 to configure everything but the IPv6 addresses. In this case the IPv6 Address(es) must be configured using SLAAC or manually Cisco interface config « ipv6 nd other-config-flag » DHCPv6 Cannot be used to configure a default route! Some drafts exist but still no RFC!© 2011 Fred Bovy. IPv6AutoConfig—2-33
  34. 34. IPv6 Autoconfiguration Modes Stateless Address Autoconfiguration §  NO DHCPv6, all the configuration is loaded with RA or or PPP Statefull DHCPv6 Autoconfiguration §  DHCPv6 provides addresses and other parameters (DNS, domaine name, SIP…) §  The Managed and the Other Config flags are set Stateless DHCPv6 Autoconfiguration §  SLAAC is used for address autoconfiguration §  DHCPv6 for the other informations (DNS, Domain Name) DHCPv6 Prefix Delegation §  The CPE which is a DHCPv6-PD Client receives a block of address (IPv6 Subnet) from the SP, the DHCPv6-PD Server. This block can be subnetted to configure multiple LAN interfaces. The CPE DHCPv6-PD Client can also be a DHCPv6 Stateless server for instance.© 2011 Fred Bovy. IPv6AutoConfig—2-34
  35. 35. Stateless Address AutoConfig Signalisation IPv6 routers signal the use of DHCPv6, if both bit are not cleared (default) then DHCPv6 is not used. §  M flag « Managed Adress Configuration » is set when address and network parameters configuration are available from DHCPv6. Must be configured on the routers. – no ipv6 nd Managed-config-flag §  O flag « Other Statefull Configuration » is set when Other parameters configuration must be found from DHCPv6 – no ipv6 nd Other-config-flag© 2011 Fred Bovy. IPv6AutoConfig—2-35
  36. 36. Stateless Address AutoConfiguration n  RFC 4862, IPv6 Stateless Address Autoconfiguration n RS/RA To request prefixes available to build addresses n DAD to test the new addresses n NO DHCPv6 Server required! Autoconfiguration is configurable on Linux!© 2011 Fred Bovy. IPv6AutoConfig—2-36
  37. 37. Stateful DHCPv6 Autoconfig Signalisation IPv6 routers signal the use of DHCPv6. Not M and O bits must be set in the RA. §  M flag « Managed Adress Configuration » is set when address and network parameters configuration are available from DHCPv6. Must be configured on the routers. ipv6 nd Managed-config-flag §  O flag « Other Statefull Configuration » is set when Other parameters configuration must be found from DHCPv6 ipv6 nd Other-config-flag© 2011 Fred Bovy. IPv6AutoConfig—2-37
  38. 38. Statefull DHCPv6 Autoconfiguration Address and Other parameters are configured from DHCPv6 DHCPv6 with Rapid Commit© 2011 Fred Bovy. IPv6AutoConfig—2-38
  39. 39. Stateless DHCPv6 Autoconfig Signalisation IPv6 Routers signal the DHCPv6 utilization §  M bit = 0 « Managed Adress Configuration » to use SLAAC for address autoconfiguration no ipv6 nd managed-config-flag §  O bit = 1 « Other Statefull Configuration » to use DHCPv6 for Other parameter configuration ipv6 nd Other-config-flag Address is configured by SLAAC Other parameters are then requested to the DHCPv6 Server© 2011 Fred Bovy. IPv6AutoConfig—2-39
  40. 40. Stateless DHCPv6 AutoconfigurationAddressconfigurationfrom the prefixreceived in theRA (SLAAC)Other parametersare given by aDHCPv6 Server DHCPv6 with Rapid Commit © 2011 Fred Bovy. IPv6AutoConfig—2-40
  41. 41. DHCP Prefix Delegation DHCPv6 PD Server allocates a block of addresses for the DHCPv6-PD Client The block received by the client is then subnetted to configure each interface © Frédéric Bovy 41© 2011 Fred Bovy. IPv6AutoConfig—2-41
  42. 42. DHCPv6-PD Client and DHCPv6 Stateless Server Host PE DHCPv6-PD Server DHCPv6-PD CPE DHCPv6 Lite Client Server ISP E1 E0 DHCP Client DHCP Server ISP Provisioning System 1.  CPE Sends DHCP Solicit with ORO = PD3.  RADIUS Responds with 2.  PE Sends RADIUS Request User’s Prefix(es) for the User 4.  PE Sends DHCP REPLY with Prefix Delegation Options 6.  Host Configures 5.  CPE Configures Addresses from Addresses Based on The Prefix on Its Downstream the Prefixes Received Interfaces, and Sends an RA. in the RA. As the O-bit O-bit Is Set to On Is on, It Sends a DHCP Information-request Message, with an 7.  CPE Sends a DHCP REPLY ORO = DNS Containing Request Options AAA DHCP ND/DHCP © 2011 Fred Bovy. IPv6AutoConfig—2-42
  43. 43. 6RD Service Providers RG Autoconfig 6rd 6rd IPv4 + IPv6 IPv4 + IPv6 IPv4 + IPv6 Core IPv4 + IPv6 BR RG IPv4 •  RG=Residential Gateway, BR=Border Router •  Native dual-stack IPv4/IPv6 in the home or office •   Simple, stateless, automatic IPv6-in-IPv4 encap and decap functions •  IPv6 traffic automatically follows IPv4 routing between CPE and BR •  BRs placed at IPv6 edge, addressed via anycast for load-balancing and resiliency •  RG Config can be pushed via TR-69, DHCP Option 212, PPP IPCP •  Standardized in RFC 5969© 2011 Fred Bovy. IPv6AutoConfig—2-43
  44. 44. Autoconfigured Address Refreshment IPv6 Autoconfiguration© 2011 Fred Bovy. IPv6AutoConfig—2-44
  45. 45. Remember the Preferred state ! n  This is the « NORMAL » state for an address in production. Each address has the two timers constantly updated from the system clock: Preferred and Valid As long as the derived Address is refreshed with RA Prefixes or the allocated address is reniewed by DHCPv6, the address state will remain Preferred! Valid Tentative Preferred Deprecated Invalid Preferred Lifetime Valid Lifetime© 2011 Fred Bovy. IPv6AutoConfig—2-45
  46. 46. Autoconfigured addresses have a finiteValid and Preferred Lifetime When the Interface has been started and is used by IPv6, each address which has been autoconfigured only has a limited Preferred and Valid Lifetime. •  Addresses derived from a Prefix advertized by a prefix received in a RA must be refreshed by another RA annoucing the same prefix with same or different Preferred and Valid Lifetime •  Addresses which are allocated by DHCPv6 also have a Valid and a Preferred Lifetime which must also be reset by DHCPv6 Reniew.© 2011 Fred Bovy. IPv6AutoConfig—2-46
  47. 47. Refreshing the SLAAC Addresses Timers •  An address which has been derived from a RA must be refreshed by new RAs advertizing the same prefix •  The RA Interval must be consistent with the Preferred and the Valid Timers for the addresses to be refreshed in time ipv6 nd ra-interval 200 seconds by default ipv6 nd ra-lifetime 1800 seconds or 30 minutes default ipv6 nd managed-config-flag ipv6 nd other-config-flag ipv6 nd prefix <prefix/mask> [Valid] [Preferred] •  To Be used by SLAAC: -  The On-Link and Autonomous Bits Must be Set -  If Preferred Lifetime > Valid lifetime, ignore the Prefix Information option. A node MAY wish to LOG a system management ERROR in this case….© 2011 Fred Bovy. IPv6AutoConfig—2-47
  48. 48. Update the Address Preferred and Valid Timers The preferred lifetime of each address is reset to the Preferred Lifetime in the received advertisement. The Valid Lifetime depends on RemainingLifetime, the remaining time to the valid lifetime expiration of the previously autoconfigured address. 1.  If the received Valid Lifetime is greater than 2 hours or greater than RemainingLifetime, set the valid lifetime of the corresponding address to the advertised Valid Lifetime. 2.  If RemainingLifetime is less than or equal to 2 hours, ignore the Prefix Information option with regards to the valid lifetime. if SeND is used, the Advertizes Valid Lifetime is used to update Valid Lifetime. 3.  Otherwise, reset the valid lifetime of the corresponding address to 2 hours.© 2011 Fred Bovy. IPv6AutoConfig—2-48
  49. 49. SLAAC Prefix Refreshed and Timers Updated by RA21001900 Unsolicited Periodic RA1600 RA Interval default: 200 seconds RA Lifetime default: 1800 seconds1400 Prefix: 2001:db8:4:1::/64 200s IPv6 On-Link, Autonomous Preferred and Valid Timers Preferred:1800, Valid:2100 at the Workstations RA are sent every 200 seconds +/-jitter Preferred: 1600-200 = 1400 seconds Valid = 2100 - 200 = 1900 seconds SLAAC Timers just Before receiving the RA: Preferred: 1600-200 = 1400 seconds Valid = 2100 - 200 = 1900 seconds After receiving the RA: 2001:db8:4:1::1/64 2001:db8:4:1::2/64 Preferred is reset to 1600 seconds initial timers: Preferred:1400, Valid:1900 Valid was 1900 seconds, RemainingLifetime= 1900 Preferred:1800, Valid: 2100 Received Valid = 2100 is greater than RemainingLifetime=1900 Same Principle than other Workstation Just before receiving RA So Valid Lifetime is reset to Received Valid Lifetime = 2100 Preference:1400, Valid: 1900 After Receiving the RA Preference: 1800, Valid: 2100 © 2011 Fred Bovy. IPv6AutoConfig—2-49
  50. 50. Theses Timers are also in DHCPv6 Addresses Addresses are coded as DHCPv6 Options •  IA Address Option (IADDR) -  The IA Address option is used to specify IPv6 addresses associated with an IA_NA (Non Temporary) or an IA_TA (Temporary). -  The IA Address (IADDR) option must be encapsulated in the Options field of an IA_NA or IA_TA option. -  The Options field encapsulates those options that are specific to this address. preferred-lifetime The preferred lifetime for the IPv6 address in the option, expressed in units of seconds. valid-lifetime The valid lifetime for the IPv6 address in the option, expressed in units of seconds.© 2011 Fred Bovy. IPv6AutoConfig—2-50
  51. 51. Address Refreshed by DHCPv6-PD Renew© 2011 Fred Bovy. IPv6AutoConfig—2-51
  52. 52. Renumbering IPv6 Autoconfiguration© 2011 Fred Bovy. IPv6AutoConfig—2-52
  53. 53. Principle of Renumbering for IPv6 Renumbering can be performed thanks to RA or DHCPv6 1.  Old prefix is announced with Preferred Lifetime very small or null and the new prefix with a normal Preferred Lifetime 2.  Hosts will have two prefixes 3.  Addresses built from the old prefix will be deprecated 4.  New connections use the new prefix 5.  After some time, all the remaining connections will be set on the new prefix 6.  Router only announces the new prefix 7.  Old prefix will be invalid© 2011 Fred Bovy. IPv6AutoConfig—2-53
  54. 54. Renumbering Scenario using RA Routers Configuration Valid interface Ethernet0 ipv6 nd prefix 2001:db8:cafe:1::/64 43200 0 Preferred ipv6 nd prefix 2001:db8:cafe:2::/64 43200 43200 Host Preferred address: 2001:db8:cafe:2:1:4567:9f0:1 Deprecated address: 2001:db8:cafe:1:4567:9f0:1 Preferred Prefix: 2001:db8:cafe:2::/64 Deprecated Prefix: 2001:db8:cafe:1::/64 RA © Frédéric Bovy 54© 2011 Fred Bovy. IPv6AutoConfig—2-54
  55. 55. Mobile IPv6: keep your home address everywhere you go, keep always online and only logout when you want to not when you move to another location! Autoconfiguration© 2011 Fred Bovy. IPv6AutoConfig—2-55
  56. 56. Mobile IPv6 for dummies… Without Mobile IPv6, everytime you visit a new access network, your network applications must be restarted using the new socket because the IPv6 Source Address has changed! With Mobile IPv6, the mobile nodes (MN) can travel and visit access networks but the applications still believe that packets are originated from and sent to the Home Network Address. On the Home Network, the Router must be a Home Agent (HA). At the begining it intercepts and forwards traffic from the Correspondant Node (CN) to the Mobile Node (MN). Once communication has started, it is possible to setup a direct tunnel between the MN and the CN. This is Route Optimization. New with IPv6, impossible with IPv4!© 2011 Fred Bovy. IPv6AutoConfig—2-56
  57. 57. Why MIPv6 never restart any session? §  The MN can roam from subnet to subnet getting a new IPv6 address for each visited network but the same home network address is always presented to the application! No need to restart any session §  The CN always sends packets to the Home Network Address and packets received by the CN are always originated from the Home Network Address!...No Magic, this is managed by Mobile IPv6 at the Network Layer so it is transparent for the Transport and Application layers© 2011 Fred Bovy. IPv6AutoConfig—2-57
  58. 58. Mobile IPv6 is supported on Linux and Free BSD §  For MAC OS X check KAME Free BSD –  KAME Mobile IPv6 How To §  http://www.kame.net/newsletter/20031007/ §  Linux – Project NATISBAD – The KAME project ported to Linux §  http://natisbad.org/MIPv6/#racoon §  Windows –  Very limited support with Windows 7 –  Only CN Mode w/o Route Optimization netsh interface ipv6 set mobility correspondentnode=enabled© 2011 Fred Bovy. IPv6AutoConfig—2-58
  59. 59. Most Important Terminology Home Agent The router which forward the traffic to the Mobile Node (MN) when the us is at home! Mobile Node The roaming user node. Home Address All the packets from the Mobile Node (MN) received by the Corresponding Node (CN) come from this source address. All the packets sent to the Mobile Node (MN) from the Corresponding Node (CN) are sent to this destination address. Home Link The link where the mobile node is permanently attached. Care-Of-Address The temporary address on the visited network. Correspondant Node The fixed node (not mobile) communicating with the Mobile Node (MN).© 2011 Fred Bovy. IPv6AutoConfig—2-59
  60. 60. Mobile Node visits a new access network §  MN must acquire its Care-of-Address (CoA) §  Autoconfiguration with SLAAC or DHCPv6…as usual! Mobile Node acquires its Care of Address from SLAAC or DHCPv6© 2011 Fred Bovy. IPv6AutoConfig—2-60
  61. 61. Mobile Node (MN) initializes its new location §  The Mobile Node (MN) registers its CoA with the Home Agent The Home Agent is Automatically discovered using an Anycast Reserved address. §  MIPv6 Signaling uses an IPv6 Mobility Option in an IPSec ESP protected tunnel ( ) §  An IPv6 in IPv6 IPSec Tunnel is setup between the Mobile Node and the Home Agent 1 2 Mobile Node© 2011 Fred Bovy. IPv6AutoConfig—2-61
  62. 62. Why the Applications don’t need to restart their Transport Connection (i.e TCP)? HA Mobile Node Out Src Out Dst In Src In Dst Src @ Dst @ 1) The HA replaces the COA MN IPv6 HA IPv6 MN IPv6 CN IPv6 src addr with the the MN MN IPv6 CN IPv6 CoA @ Home @ @ IPv6 Home Address. Home @ @Out Src Out Dst In Src In Dst Src @ Dst @ 2) The HA replaces the HA MN IPv6 CN IPv6 MN IPv6 dst addr with the the MN CN IPv6 MN IPv6HA IPv6 @ CoA @ Home @ IPv6 Home Address @ Home @© 2011 Fred Bovy. IPv6AutoConfig—2-62
  63. 63. Can we build a direct tunnel to bypass the HA? 1.  The Corresponding Node (CN) must support Mobile IPv6 with Route Optimization 2.  The Mobile Node (MN) initiates this by sending a Binding Update to the Corresponding Node (CN) 3.  The Corresponding Node (CN) sends Keygen Tokens to the Mobile Node (MN) at both its CoA and its Home Address. If the MN receives both, it has proven its identity to the CN! It receives a Binding Ack and the Tunnel setup! te Upda Bin ding in g Ac k MN proves to the CN that it Bind receives the Keygen Tokens© 2011 Fred Bovy. Mobile Node IPv6AutoConfig—2-63
  64. 64. Why the CN Application receives packets of the MN originated from the MN Home Network Address? The CN replaces the MN IPv6 Mobile Node CoA with the IPv6 Home @ from the Destination Option: Datagram comes from the MN Dst Opt Src @ Dst @ MN IPv6 MN IPv6 CN IPv6 Home @ CoA @© 2011 Fred Bovy. IPv6AutoConfig—2-64
  65. 65. Why the MN Application receives a packet with the Home Network Addr as the dst Addr? Mobile Node The MN replaces the MN IPv6 CoA with the MN IPv6 Home @ from the Routing Option: Datagram is sent to the MN Home @ Src @ Dst @ Routing CN IPv6 MN IPv6 MN IPv6 @ CoA Home @© 2011 Fred Bovy. IPv6AutoConfig—2-65
  66. 66. Mobile IPv6 Applications § Proxy Mobile IPv6 (PMIPv6) for LTE and 4G § Mobile Router or Nemo –  RFC3963: NEMO Basic Support Protocol –  A router is moving with all its networks and connected hosts –  RFC5555: Mobile IPv6 Support for Dual Stack Hosts and Routers –  UMIP Project on Linux –  http://natisbad.org/MIPv6/#umip § Ad Hoc dynamic mobile networks or Manet –  Nodes discover their neighbors dynamically and join the network §  Wireless Sensors Networks (6LoWPAN)© 2011 Fred Bovy. IPv6AutoConfig—2-66
  67. 67. Proxy Mobile IPv6 introduced with LTE The LMA provides the Local Mobile IPv6 HA function1.  The MN enters the PMIPv6 Mobility Local Mobility domain and attach to an Anchor Anchor (LMA1) access-link. (LMA2)2.  The MAG verifies the MN Identity and Authorizations.3.  If OK, the MAG helps the MN to get all the configuration: address, default gateway,… Mobile Mobile IPv6 Network4.  The MN considers the Access Gateway Access Gateway PMIPv6 domain as a link (MAG1) Mobile Access (MAG3) Gateway (MAG2) Mobile Node MN1 Mobile Node Authentication MN2 To offload the Mobile IPv6 Signaling and IPSec Protection complexity from the Smartphones to a Network device © 2011 Fred Bovy. IPv6AutoConfig—2-67
  68. 68. Proxy MIPv6 converts ND requests to MIPv6 Signaling1.  The MN sends a RS (Router Solicitation) to the MAG.2.  For updating the LMA about the MN location, the MAG sends a PBU (Proxy Binding Update) to the MN’s LMA. Local The LMA provides the Mobility Mobile IPv6 HA function3.  The LMA sends a PBA (Proxy Binding Acknowledgement) Anchor including the MN home network prefixes. It creates the Binding (LMA1) Cache entry and sets up its endpoint of the bi-directional tunnel to the MAG.4.  The MAG sends a RA: Router Advertisement 2 PBU to the MN. The MAG can emulate the MN’s Home Link PBA including the MN home network Mobile prefixe(s)5.  The MN can be configured Access Gateway using SLAAC or DHCPv6 (MAG1) 3n  PBA/PBU Signaling must be Mobile Node MN1 protected with IPSec !n  Data Protection is Optional RS 1 RA 4© 2011 Fred Bovy. IPv6AutoConfig—2-68
  69. 69. The Mobile Router: Nemo §  Mobile Router can receive a block of addresses from DHCPv6-PD §  The Mobile Router Can be a Smartphone to provide access Internet via 4G to local nodes with WiFi or Bluetooth access. Home Agent Corresponding Home Network IPv6 Internet node WLAN 3G Network NEMO Router Dual Stack avec DSMIPv6 Bluetooth or WiFi IPv4 IPv6© 2011 Fred Bovy. IPv6AutoConfig—2-69
  70. 70. Mobile Ad Hoc Networking: Manet With MANET, the nodes discover automatically configure their neighbors and build a dynamic Network To manage the neighbors a node can use: –  OSPFv3 Wireless –  EIGRP Uplink What if these nodes have sensors?© 2011 Fred Bovy. IPv6AutoConfig—2-70
  71. 71. Wireless Sensors Networks (6LoWPAN)The Network of Sensors can be built dynamicallyusing Dynamic MANET On-demand for6LoWPAN (DYMO-low).Possible Applications:• Localized weather monitoring• Structural Health monitoring (Earthquake prone areas)• Battlefield troop detection, movement• Intelligent Transportation Systems (ITS)• Green app: Building environment management– Lights, HVAC, Security Access, smart power outlets, etc.– Building demo - ~20% MRC cost savings © 2011 Fred Bovy. IPv6AutoConfig—2-71
  72. 72. Thank you for attending!This concludes IPv6 Autoconfiguration In-depth PresentationFred BovyIPv6 Forum Gold Certified EngineerIPv6 Forum Gold Certified TrainerCISCO 15 years CCIE #3013CISCO 18 years CCSI #33517 (before was #95003)Meet me onTwitter: FredBovySkype: FredericBovyBlog: http://www.fredbovy.com/Go46Email: fred@fredbovy.com
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