Does IPv6 work in a LAN environment?

So I have been introduced about IPv6 at school. (In fact one of our assignment is to do a IPv4 to IPv6 proxy in the labs.)

Unfortunately there are currently no ISP in my country that offers IPv6. However I guess I am just geeky enough that I like to set up an IPv6 in my LAN to "play" around with... like ssh from other machines and using my internal web pages via IPv6.

So I am wondering how does it work, or does it work at all in a LAN? From what I have read from Google, the address space for IPv6 is so large that you simply don't need NAT anymore, and many tutorials and how-to's basically teach you how to get a free IPv6 over IPv4 tunneuling and basically just use whatever IP you get from the service...

What I like to know is, is it at all possible to set up a private IPv6 network that doesn't connect to the Internet? It looks like its got self-assigned address too and doesn't need DHCP...

Basically I am not sure where to start if I want an internal IPv6 network to play with.

Thanks.

Hi,
Of course YOU CAN set up a private IPv6 on LAN, i just did that 8 years ago at college!!! IPv6 address on each of your host may just be derivated/built with the IPv4 address... (not sure though its been long since :D) Make sure to test your config with IPv6 aware application (ping6 etc ...)

Yes I have play with setting up IPv6 in the labs, to the point where I can start surfing ipv6.google.com, and of course we tried out stuff like ping6 and traceroute6.

The labs however, all have "public" IPv6 address, there was no NAT, all the packets are just route straight to the net and straignt back via routers/gateways.

I guess I am wondering how should a private network for IPv6 to set up... you know on IPv4 there are special address space reserved for private use, 10.0.0.0/8 for e.g... I am not aware of such thing for IPv6, so does that mean you just use random IPv6 address for IPv6? By random I mean, set up your own rule, map to existing IPv4 ip range or something, just not some specific thing like 10.0.0.0/8.

Two choices. The first being wasteful. Use allocated space; however, don't announce it to the Internet. Not a briliant idea; however quite doable. Keep in mind that IPv6 space is quite large; yet it's been setup as follows:

http://www.iana.org/assignments/ipv6-address-space

IPv6 Prefix           Allocation              Reference      Note
-----------           ----------              ---------      ----
0000::/8              Reserved by IETF        [RFC4291]      [1] [5] 
0100::/8              Reserved by IETF        [RFC4291]
0200::/7              Reserved by IETF        [RFC4048]      [2]
0400::/6              Reserved by IETF        [RFC4291]
0800::/5              Reserved by IETF        [RFC4291]
1000::/4              Reserved by IETF        [RFC4291]
2000::/3              Global Unicast          [RFC4291]      [3]
4000::/3              Reserved by IETF        [RFC4291]
6000::/3              Reserved by IETF        [RFC4291]
8000::/3              Reserved by IETF        [RFC4291]
A000::/3              Reserved by IETF        [RFC4291]
C000::/3              Reserved by IETF        [RFC4291]
E000::/4              Reserved by IETF        [RFC4291]
F000::/5              Reserved by IETF        [RFC4291]
F800::/6              Reserved by IETF        [RFC4291]
FC00::/7              Unique Local Unicast    [RFC4193]
FE00::/9              Reserved by IETF        [RFC4291]
FE80::/10             Link Local Unicast      [RFC4291]
FEC0::/10             Reserved by IETF        [RFC3879]      [4]
FF00::/8              Multicast               [RFC4291]

What you saw with your local addresess was from the Fe80::/10 space. If you setup a new network and enable IPv6 on those interfaces, then you will get new addresses (unique addesses) within that space. It's not going to route to the Internet and in fact it's only going to be on that segment.

Look at joe-random-cisco-box:

!
interface FastEthernet0/0
 ...
 ipv6 address 2001:470:####:####::/64 eui-64
 ipv6 enable
 ...
!

In that example; the interface has an IPv6 address that's routable. If you remove the "ipv6 address" line; then you get an interface with just a link local address.

Same goes on Linux/Unix. (With different commands).

$ ifconfig eth0
eth0    Link encap:Ethernet  HWaddr 00:14:D1:13:7F:33
          ...
          inet6 addr: fe80::214:d1ff:fe13:7f33/64 Scope:Link
          ...
$ 

It's just not as pretty as 10.0.0.0 yet it's your local private unrouted verfy own network!

BTW: I can't help but plug http://www.tunnelbroker.net/ as I work for Hurricane Electric. Bring up another machine (in 5 mins) running IPv6 that will be "somewhere else" in IPv6 address space and then you can communicate between your sites vs. ping6'ing google. :slight_smile:

Enjoy,

Martin