Experience the IPv6 Internet with Teredo

　Until the third, we have explained that IPv6 can be used on small LANs, but in the future, we will change the viewpoint and take up the connection to the IPv6 Internet.This time, let's experience the Internet of IPv6 using the "tunnel connection" from the current Internet connection environment.

Frequently IPv4 Internet connection environment

　The premise of this article, "IPv4 Internet connection environment, which is common," is an Internet connection environment on IPv4 using the NAT (network address conversion) function of the router (Fig. 1).The NAT router does not have to be made by Yamaha.Buffalo, NEC Access Technica, or rental routers from ISP are fine.Even if the router is not compatible with IPv6, you can experience the IPv6 Internet with almost no problem.The same is true no matter where the ISP is.

Figure 1 Currently common IPv4 connection environment

　Conversely, if the PC is connected directly to the Internet with a "FLET'S connection tool" without using a router, or if an address is assigned by DHCP, such as the Internet connection of CATV operators, this article does not work.。First, check your environment.

Use the IPv6 tunnel

　There are several ways to connect a PC to the IPv6 Internet in an IPv4 Internet connection environment with a NAT router.Nevertheless, in principle, all use the technology called the IPv6 Tunnel (IPv6 Over IPv4 tunnel) (Figure 2).

Figure 2 Concept of IPv6 tunnel

　This is built between the IPv6 tunnel between the user's computer (① in Fig. 2) and the IPv6 connection gateway (⑤ in FIG. 2), and it is built, andIn that section, the IPv6 packet is carried on the data part of the IPv4 packet (④ in Fig. 2).

　At this time, the network between the PC and the IPv6 connection gateway does not have to be compatible with IPv6.All you have to do is pass the IPv4 packet.The IPv6 Internet can be used even if the user switch (② in Fig. 2), the router (③ in Fig. 2), and the contracted provider's devices and networks are only compatible with IPv4.As now, most ISP supports only IPv4, and it is an essential technology to use IPv6.

　The IPv6 connection service using the IPv6 tunnel is provided by multiple service operators.In the meantime, we will introduce some simple ones in order.

Use free public service

　For the time being, the easiest environment for individuals to use IPv6 is the free public service.There is no need for a contract with a provider, etc., the setting work is extremely low, and it is not expensive.The disadvantage is that only free users may lack reliability and stability.

　There are several free public services, but the most easy is the four IPv6 tunnel connections installed in Windows.This time, I will explain the method of connecting a tunnel called “Teredo”.

Use low -cost commercial services

　The free public service is easy, but there are some unstable places.Therefore, as a stable commercial service, there is "OCN IPv6" of NTT Communications.Although it is not free, it is relatively inexpensive (315 yen to 577.5 yen per month), even if you use OCN for Internet connection, you can use it either ISP other than OCN.This is used for special software, so no command operation is required.In OCN IPv6, it is possible to use a PC with a dedicated software as an IPv6 router, and all PCs in the same LAN can be connected to the Internet by IPv6.

First, delete the global IPv6 address

　Before explaining the procedure to connect to the Internet on IPv6, there are precautions.Before performing the procedure to be described from here, it is necessary to delete the IPv6 settings that have been performed by the previous time.This is because if the global IPv6 address is assigned to the Windows 7/Vista/XP LAN interface, the procedure to be explained may not be able to be connected well.

　In particular,

# no ipv6 lan1 rtadv send 1# no ipv6 lan2 rtadv send 2# no ipv6 prefix 1# no ipv6 prefix 2# no ipv6 lan1 address fd00:0:0:1::1/64# no ipv6 lan2 address fd00:0:0:2::1/64

1. ルーターのIPv6の設定を削除する（リスト1）
2. PCのIPv6設定をリセットする（画面1）

Screen 1 Reset IPv6 settings on PC

You need to do two tasks.

　Readers who have practiced the contents of the article up to the previous article should be careful.

Try using Windows standard functions (Teredo)

　Windows 7 is a means to connect from IPv4 Internet connection environment to IPv6 Internet.

1. Teredo
2. 6to4
3. 6over4
4. ISATAP

The four types of "IPv6 tunnels" are implemented (the same is true for Windows XP/Vista).Among them, I would like to pay particular attention to Teredo.This is because it is most suitable for the mainstream of the current Internet connection, that is, the premise of this article, the IPv4 Internet connection environment with NAT routers.

　In Windows 7 and Vista, when a private IPv4 address is assigned to a PC LAN interface, a virtual interface for the Teredo tunnel is automatically configured.At this time, when IPCONFIG is executed, you can see that the global IPv6 address is set in the last Tunnel Adapter (screen 2).

Check the Teredo virtual interface on IPCONFIG

　Teredo is a client tora bar -type service and is connected to Microsoft's Teredo server in the initial setting of Windows 7.Let's check the status of the Teredo tunnel in Netsh (screen 3).

See the condition of the Teredo tunnel on Netsh.

　The server name says "teredo.ipv6.microsoft.com."Also, if the state is "Qualified", the Teredo tunnel works normally, but in the case of other values, it is in preparation or cannot be used.If the Windows firewall is disabled, the setting of the Teredo will fail, so be sure to enable it.

　It is already possible to connect to the Internet with IPv6 on the screen 3.Speaking of the IPv6 test site, "Odoru turtle (http://www.kame.net)" is the most famous, but here you will see OCN's "IPv6 Communication Confirmation Site" (screen 4).

Screen 4 See OCN IPv6 communication confirmation site on Internet Explorer

　On screen 4, please pay attention to the address bar.The IPv6 address is specified as "http: // [2001: 218: 2001: 3005: 7f]/" instead of the host name.This is because via Teredo cannot convert to IPv6 address using DNS.However, since the hosts file is valid, if you register a famous site, you will be able to access by name (List 2).

127.0.0.1 localhost2001:200:dff:fff1:216:3eff:feb1:44d7kame# www.kame.net2001:218:2001:3005::7f ocnipv6# www.ocnipv6.jp

(Next page, following the "Teredo mechanism")