Enabling your network for IPv6

The advantages for using IPv6 are very well published on many websites, the most obvious is the increased address space. For me, I wanted to be able to give all my computers world routeable addresses which will allow me to connect directly to other computers on the internet without using NAT and dealing with the problems that NAT imposes on protocols like SIP or H.232 for video conferencing. Also, some protocols like FTP require protocol translators to work through NAT or will simple be limited to one mode of operation or the other. For example, a FTP client behind an NAT router can only initiate passive data transfers, but an FTP server behind an NAT router can only accept active transfers. It is therefore impossible to talk to a FTP server behind an NAT router from a FTP client behind a difference NAT router without special provisions. I have since enabled several services including WWW, Mail, IRC, DNS, and others using IPv6. The webserver which hosts multiple domains gives each domain a unique IPv6 address, something that was not possible for me previously.

The first step to enabling IPv6 on your network is to see if your ISP supports native connections. As most ISPs probably won't even know what your talking about, that won't work for most people. Luckily, they don't need to support it as there are many free IPv6 tunnel brokers out their to choose from. I chose XS26 as they fit my needs the best. They gave me a no hassle, production, /48 IPv6 prefix. The RFCs for IPv6 currently state IPv6 customers, whether they be small or medium sized business or just a DSL or Dial-up customer should receive a global /48 prefix on connection. Since the last 64 bits are reserved as a host identifier, this give the user 16 bits to play with for assigning to subnet numbers in the network. The last 64 bits are automatically filled in by the host and only the IPv6 routers need to be configured to advertise the /64 bit prefix for the local subnet and possibly a default router.

After you have chosen your tunnel broker, you need to setup a tunnel with them. Depending on the broker, they may require you to run special software. I liked XS26 because I could just use the native tunnel support available in most IPv6 systems. On Linux, this is the sit tunnel, and on FreeBSD it's the gif tunnel. For this example, my ISP offered me a tunnel from a server with an IPv4 address of and my local router has an outside IPv6 address of This numbers are purely fictitious, of course.

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