The Hitchhikers’ Guide to IPv6

1. The Hitchhikers’ Guide to IPv6 Jeff Schwab

2. Don’tPanic!

3. It’s the End of the World(as we know it) • February 3, 2011 • IANA (Internet Assigned Numbers Authority) hands out the last 5 available /8 address pools to ARIN, LACNIC, AFRINIC, RIPE, and APNIC • Over the next several months these pools will be exhausted • After that, requests will be queued until addresses are returned to the pool

4. A Little History • Address space exhaustion first discussed in the early 1990s! • Three competing proposals: • 64 bit SIPP (Simple Internet Protocol Plus) • 128 bit SIPP • Variable length address “TUBA” (ISO based) • In 1994, at Toronto meeting IETF announced plans to use 128 bit SIPP

5. How big is it? • 2128 = 3.40282367 * 1038 • Assuming one address per cubic meter, this gives us a sphere just short of the orbit of Neptune • Certainly, this will be enough • After all, a PC only needs 64K of memory

6. Addressing • IPv4 addresses are usually represented as: • Four period separated decimals (0-255) • 128.210.11.1 • Stored in DNS “A” records • IPv6 addresses are usually represented as: • Eight colon separated hex numbers (0-FFFF) • 2001:18E8:0800:F4FF:0000:0000:0000:0001 • Stored in DNS “AAAA” records • Any one group of consecutive zeros can be replaced by :: • 2001:18E8:800:F4FF::1

7. Unicast IPv6 Addresses • Basic Format • Host Part • Manually configured • Mapped from EUI-48 (MAC address) • Mapped rom EUI-64 (Infiniband/Firewire) • Concerns about privacy/tracking if MAC address is used

8. IPv6 “Network” Addresses • Many different proposals floated • Two early favorites • 1) Provider based addressing • 13 bits at top level (8192 top level “routes”) • Severely limits number of “Tier-1” providers • Good for routing table • 2) Geographic addressing • Good for routing and aggregation • Requires more cooperation among providers than we can ever expect

9. The Reality • Provider/entity based addressing • Provider part comes from regional registry (ARIN, etc.) • End sites customarily receive a /48 • Residential users will get less • But we still may be able to get rid of NAT

10. More Reality • Providers can actually get more than a /32 • Almost any large enterprise can receive a /32 • The current definition of enterprise is rather loosely interpreted

11. An Example • ARIN allocated 2001:18E8::/32 to the Indiana Gigapop • Indiana Gigapop allocated 2001:18E8:0800/44 to Purdue University • Purdue University allocated 2001:18E8:0800/48 to the West Lafayette campus • Initially, West Lafayette campus can allocate 65,536 subnets with 264 potential hosts on each

12. Other Addresses • Multicast • Start with ff00::/8 • Scoping rules used to limit propagation • Anycast • Highest 128 interface addresses on a subnet • Broadcast • Gone. Can use scoped multicast instead

13. Brief Down and Dirty • IPv6 Packet Headers • Fixed length header to simplify processing • IPv4 headers had variable length due to options

14. Some Comments • Hop Limit – Analogous to IPv4 TTL • Next Header – Type of Extension header (Layer 3 or Layer 4) – can be chained • Payload Length – Number of octets (unless jumbo extension header follows)

15. Extension Headers • Replace (and augment) IPv4 options • Source routing • Authentication • Encryption • Layer-4 protocols • TCP, UDP, ICMP

16. Layer 4 Protocols • TCP and UDP • Bit for bit the same as with IPv4 • ICMP • Slightly modified, all IPv4 functionality is there • Includes some old IGMP (multicast) functionality • Adds functions for neighbor/router discovery • ARP • Gone! • Functionality merged into ICMP

17. Routing • RIP • Still there • OSPF • Parallel to IPv4, but two do not interact • BGP • Can support both IPv4 and IPv6 in same session

18. Host Configuration • Static Manual Configuration • Router gateway, network address/mask, DNS • Just like today only numbers are larger • More typing • Two Network based options • SLAAC • DHCPv6

19. SLAAC • StateLessAutomatic Address Configuration • IPv6 “Plug and Play” • Uses ICMP to find router and local network • Host part of address comes from MAC address • Some OS’s (Windows) randomize this for privacy • But “Privacy addresses” may break firewalls • But… No DNS info • No generally accepted extensions for DNS

20. DHCPv6 • Works similarly to DHCP for IPv4 • DHCPv6 servers now available • But… Currently not implemented by Apple

21. How do we get there from here? • Routers and switches will need to support IPv6 • Most current generation hardware does IPv6 to some extent. • Routing protocols are available for IPv6 • Older hardware will need to be updated • May have enough time to work into LCR plan • Wireless is usually easy if just bridging

22. Other Network Hardware • Firewalls and Load Balancers • Support for IPv6 mostly just starting • Some upgraded code for existing hardware • May require a forklift upgrade • Beating up vendors can help

23. Hosts • IPv6 is supported in most modern OS’s • Generally enabled by default • Windows XP does not support DNS over IPv6 • “Privacy addresses” on by default in Windows • Apple does not support DHCPv6

24. Services • Server side • Many critical pieces already have IPv6 aware versions • Apache, Sendmail, Bind, MySQL • Client side • Most services just rely on underlying OS support • Major browsers are IPv6 aware • Firefox, Opera, Safari

25. What can we do with IPv6? • Many sites are enabling IPv6 • Industry does not want to lose IPv6 clientelle • Facebook, Netflix, and Google are IPv6 ready • Google requires whitelisting currently

26. Surviving the transition • Eventually, IPv6 will be the only protocol • Probably after most of us are retired • Meanwhile, we need to work in both worlds • We will start with islands of IPv6 in an IPv4 world • Will transition to islands of IPv4 in an IPv6 world • Tunnels will evolve to carry traffic between the islands • Will need to support both protocols and forms of tunneling and NAT servers to support access

27. Best Option - Dual Stack • Host supports and talks to both IPv6 and IPv4 • Cleanest answer • Future-proof • Generally transparent to end user • As long as everything is “working correctly” • Difficult to debug when things go wrong

28. Accessing IPv6 from IPv4 • Not enough address bits to be easy • “DS-Lite” – Dual Stack Light • NAT based solution • Needs to play DNS tricks • Rumored Comcast trial

29. Accessing IPv4 from IPv6 • DNS Alg (DNS64) • Special resolver on IPv6-only network • If a AAAA record, use it • Else put address from A record into bottom 32 bits of special IPv6 prefix • May not work well with DNSSEC • NAT64 • Relay router • Dual stack on outside, IPv6 only on inside • State table to maintain IPv4 pool • “Real” IPv6 addresses used unchanged • Special addresses from DNS64 mapped back to IPv4 addresses

30. Alternatives to IPv6 • NATs • Lots of NATs • Lots and lots and lots of NATs • Performance suffers • End to end applications fail

31. Consequences of not doing IPv6 • Lose access to overseas markets/clients • Lose access when travelling • New remote sites may not be able to get IPv4 space • Eventually lose access to domestic markets/clients

32. Costs of transition to IPv6 • “Unfunded Mandate” • Replace as much hardware as possible in LCR • DO NOT buy any new hardware that isn’t IPv6 ready • Routers • Firewalls • Network Appliances • Pressure your vendors for software upgrades, etc. • Engineering costs to set up new address scheme • Cost of running transitional appliances

33. Where do I start? • Work IPv6 into hardware LCR • Prepare your networking infrastructure for IPv6 • Your “Internet presence” (servers) will be most painful conversion • Printers and other internal only appliances are lowest priority

34. And I Feel Fine… • It’s the End of the World as We Know it • We can’t ignore the problem • We have some time • Start experimenting! • World IPv6 Day – June 8, 2011

35. That’s all folks! • Questions? • Comments? • Live Poultry? • Acknowledgements: • Michael Lambert, Pittsburg Supercomputing Center • Internet2 IPv6 Working Group