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Summary

Summary. Peer to peer applications and IPv6 Microsoft Three-Degrees IPv6 transition mechanisms used by Three-Degrees: 6to4 Teredo. Peer to Peer Applications and NATs. NATs break end to end End to end communications would be useful in a P2P context…. Private IPv4 (DSL…). Public IPv4.

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Summary

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  1. Summary • Peer to peer applications and IPv6 • Microsoft Three-Degrees • IPv6 transition mechanisms used by Three-Degrees: • 6to4 • Teredo

  2. Peer to Peer Applications and NATs • NATs break end to end • End to end communications would be useful in a P2P context… Private IPv4 (DSL…) Public IPv4 Private IPv4 (DSL…) NAT P2P NAT P2P

  3. First type of solution • Use an intermediate server • Complex solution to design • Operation of the server is not free Private IPv4 (DSL…) Public IPv4 Private IPv4 (DSL…) NAT P2P NAT P2P Server

  4. IPv6 based solutions • Simpler solution • Application is cheaper to design • No server required, but one can be used if needed… Customer IPv6 (DSL…) Public IPv6 Customer IPv6 (DSL…) P2P P2P

  5. Microsoft ThreeDegrees • 3° is a P2P software that connects small groups of users who know and trust one another. • Currently a beta test application on Windows XP SP1 • several downloads (10 000) • First feed-backs are positive • Use IPv6 only (No IPv4), because the application is easier to design. • http://www.threedegrees.com

  6. Three Degrees and IPv6 • IPv6 is not available everywhere: • It first appears as isolated islands in the IPv4 Internet • Several migration techniques exist: • Dual stack • Automatic tunneling: 6to4 and Teredo • Configured tunnels, tunnel broker • Translation • Application level gateways • Transition mechanisms bring additional complexity • Only needed during transition. • Most of the complexity is in the OS, not in the application. • The cost for the infrastructure is low.

  7. Dual Stack • Deploy native IPv6 in addition to IPv4 everywhere: • Routers • Servers: DNS, Radius… • Hosts • Slow deployment => not present everywhere • Should be a long term goal

  8. 6to4 • Goals: • Allow the interconnection of IPv6 sites through a service provider network that only support IPv4. • Connection of IPv6 sites to the IPv6 Internet through a service provider network that only support IPv4. • Does not require the provision of IPv6 prefixes by the ISP • Use of a global IPv6 prefix for each site derived from the site’s IPv4 global address.

  9. 6to4 – Interconnection of IPv6 sites

  10. 6to4 – Access to the IPv6 Internet

  11. 6to4 - Limitations • 6to4 relays can be vulnerable to denial of service attacks • Filtering is needed in relays! • The entity that operates the 6to4 relay has little means in order to control who is using the service. • NATs break 6to4, if they are not co-located!

  12. TEREDO • Goals: • Provide IPv6 connectivity across one or several NATs • Tunneling IPv6 packets over UDPv4 through the NAT • Client/server/relay architecture • Use of a new address format

  13. Teredo Teredo tunnel: IPv6 in UDPv4 IPv6 Public IPv4 Private IPv4 NAT

  14. Client / relay / server Server 1 Client 2 Public IPv4 3 4 6 5 Private IPv4 Public IPv6 NAT Relay

  15. Teredo address format 16 bits 32 bits 32 bits 16 bits 32 bits • Teredo IPv6 prefix • IPv4 address: global address of the server • Flags: Cone or Symmetric NAT • Port: port number to be used with the IPv4 address • The “client IPv4 field” contains the global address of the NAT Teredo prefix IPv4 @ Flags Client IPv4 Port

  16. Teredo limitations • Not well known yet, but probably similar to 6to4 • Vulnerability to DoS attacks on relay, • The entity that operates the 6to4 relay has little means in order to control who is using the service • Some NATs are not supported • Teredo relays are not deployed! • Lack of implementation in routers • Teredo prefix is not advertised in the IPv6 Internet

  17. Three Degrees and IPv6 transition • Three Degrees processes as follow: • If a native IPv6 address is available on the host, use it, • Else • If IPv4 addresses are public addresses, then use 6to4 • NATs are not supposed to be in the way • If IPv4 addresses are private addresses, then use Teredo • NAT is likely in the way.

  18. Typical deployment Native IPv6 IPv6 + IPv4 Internet 6to4 tunnel Teredo tunnel Teredo server 6to4 relay Teredo relay NAT IPv4 Internet NAT

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