This document provides information about IP address conversion between IPv4 and IPv6, as well as common IP address ranges and formats. It also discusses some web application concerns and considerations for supporting both IPv4 and IPv6, such as additional validation of IPv4-embedded IPv6 addresses, larger space required for storing IPv6 addresses in databases, and ensuring log analyzers and tools support the IPv6 format. Automatic and static configuration techniques for IPv6, including link-local addresses, public address blocks, tunneling protocols like Teredo and 6to4, and their address formats are outlined.

2. IP Conversion
 127.0.0.1  ::1
 Link-local 169.254.0.0/16  FE80::/10 (Auto EUI-64)
 Example address  2001:db8::/32
(192.0.2.0/24)
 Private address  FC00::/7
(10.0.0.0/8,  FC00::/8
172.16.0.0/12,  FD00::/8
192.168.0.0/16)
IPv4 IPv6

3. Link-local?
 fe80::/10
 Use to ask:
 Anyone else here on this link?
 Anyone here with a special address
(e.g. looking for a router)?
 Announce for rules (router advertise).

4. Public address
 2000::/3
 2xxx::/4
 3xxx::/4
 2001:0::/32  Teredo address
 2002::/16  6to4 address
 3ffe::/16  6bone (test) address

5. Special address format
 ::ffff:192.0.2.1  IPv4 embedded address

7. Web application concerns
 Additional validation for v4embed address
 Apache can handle this case.
 Lighttpd+FastCGI is known to have this issue

8. Web application concerns
 IP Logging in database
 Require
39 chars
for IPv6
address

9. Web application concerns
 Display space in web page

10. Web application concerns
 Display space in web page

11. Web application concerns
 GeoIP requires additional IPv6 database
 Log analyzer (webalizer, awstats) and
v4embed address

12. Web application concerns
 Direct connect to IPv6 address:
use [ ] brackets like “[2001:db8::1]”
 Example:

13. Web application concerns
 Communicating to other site by curl,
file_get_contents, …
 IPv4-only servers or some with incorrect
ipv6 setting might have problem when
access to dual-stack sites ex: Facebook,
Google
○ Server try to connect to ipv6 first, then ipv4.
○ Some more latency for retry with ipv4.

15. Automatic configuration
 Just enable IPv6 !
 Router will advertise itself and prefix /64
to use in that network.
 Client will automatically assign address
with EUI-64 or Pseudo-random address.

16. Static Configuration

17. Tunnelling
 Teredo (Windows)
 6to4 (Linux)

18. Teredo
 Automated tunnel under windows vista/7
 Use UDPv4 to pass thru NAT under IPv4
 No static address can be use as a server!
 Connects only to direct IP's

19. Teredo

20. Teredo
 http://[2404:8800:804::1]/

21. 6to4 Tunnel

22. 6to4 Tunnel
 Traffic send to nearest anycasted router IP:
192.88.99.1
 Nearest public router: Uninet, Equinix SG

23. 6to4 Tunnel
 Convert and automatically tunnelled
IPv4 into IPv6 address
 IPv6 prefix: 2002::/48

24. 6to4 Configuration : Red
Hat
 IPV6_DEFAULTDEV=tun6to4
 IPV6INIT=yes
 IPV6TO4INIT=yes

25. 6to4 Tunnel

27. Test your connectivity
 http://www.testipv6.com/

29. Something need to know
http://upic.me/ access
160000
140000
120000
100000
80000
Pageviews/day
60000
40000
20000
0
IPv4 IPv6

30. @icez