prefix length is first 64 bits

VT is

2001:468:c80::/48

Global is

2000::/3

IPv6to4 is

2002::/16

IPv6to4 for VT is

2002:80ad::/32
2002:c652::/32

if these 2002 addresses appear, it could cause it to search 40 hops away. Turn off IPv6to4

Link LocalL

fe80::/10

Multicast:

ff00:/8

All node Multicast:

ff01::

Multicast on link local

ff02::

loopback

::1

http://rdweb.cns.vt.edu/wiki

http://www.sixxs.net

Good firefox plugin: showIP

http://www.kame.net

http://ipv6.vt.edu

host.dept.ip6.vt.edu → AAAA

host.dept.vt.edu → A

host4.dept.vt.edu used for ip4 addresses only

2002:… addresses are for IPv6to4 gateways

If only fe80::, maybe router discovery is off

http://www.ipv4.sixxs.net/wiki/Installing_a_Subnet

independence ~ # cat /etc/radvd.conf

interface eth0
{
       AdvSendAdvert on;
       prefix 2001:4978:215::/64
       {
               AdvOnLink on;
               AdvAutonomous on;
               AdvRouterAddr on;
       };
};

for independence:

 ip addr add 2001:4978:215::1/64 dev eth0
 /etc/init.d/radvd start

Hostname: uschi02.sixxs.net

This PoP provides tunnels from the following prefixes:

• 2001:4978:f::/48 of size /64

Subnets are allocated out of:

• 2001:4978:100::/40 of size /48
• 2001:4978:200::/40 of size /48

address for independence as reported by ssh login from independence to riccioli:

cl-734.chi-02.us.sixxs.net

for thinkpad-steve as reported by ssh login to riccioli:

2001:4978:215:0:218:deff:fe4b:2569

sixxs                        2001:4978:f:2dd::1 gw-734.chi-02.us.sixxs.net
independence sixxs external  2001:4978:f:2dd::2 cl-734.chi-02.us.sixxs.net
independence eth0 internal   2001:4978:215::1
thinkpad wlan0               2001:4978:215:0:218:deff:fe4b:2569
bacchus                      2001:468:c80:610c:230:48ff:fe8f:77dd/64
chernabog.cc.ipv6.vt.edu     2001:0468:0c80:2105:0000:025e:42da:ffc7 (tried to connect using SPT=80)
inbound.smtp.vt.edu          2001:468:c80:2106:0:240:5040:1614
hephaistos                   2001:468:c80:610c:24f:4eff:fe0f:fd4a/64

http://www.linux.com/learn/tutorials/428331-ipv6-crash-course-for-linux

ff02::1 is short for ff02:0:0:0:0:0:0:1, which is a special link-local multicast address for discovering all link-local hosts

$ ping6 -c4 -I eth0 ff02::1

ip -6 neigh show

nud reachable means the network unreachability detection status is reachable

ping6 -c4 -I eth0  fe80::(rest of address)

/etc/hosts file of each PC:

fe80::20b:6aff:feef:7e8d  fatfreddy
fe80::221:97ff:feed:ef01  phineas
fe80::3f1:4baf:a7dd:ba4f  franklin

Now you can ping6 by hostname:

$ ping6 -I eth0 phineas

This is how you establish an SSH session:

ssh phineas@fe80::221:97ff:feed:ef01%eth0

Again, you must specify the network interface name on your PC, and you must do it as shown, appended with a percent sign and no spaces. scp has its own fiendish syntax quirks:

$ scp test.txt phineas@\[fe80::221:97ff:feed:ef01%eth0\]:
phineas@fe80::221:97ff:feed: ef01%eth0's password:
test.txt 100%   19     0.0KB/s   00:00 

The IPv6 address must be enclosed in square braces, including the interface name, and the braces must be escaped.

Let's fake one up for practice and assign it to a network interface:

# ip -6 addr add 2001::1/64 dev eth0

Now let's check our work:

$ ifconfig eth0 |grep "inet6 addr:"

        inet6 addr: 2001::1/64  Scope:Global
        inet6 addr: fe80::20b:6aff:feef:7e8d/64 Scope:Link

If you need to remove it, use the del command with the ip utility:

# ip -6 addr del 2001::1/64 dev eth0

http://www.linux.com/learn/tutorials/432537-another-ipv6-crash-course-for-linux-real-ipv6-addresses-routing-name-service

these iptables rule block all IPv6 traffic from entering or leaving your LAN:

ip6tables -P output drop
ip6tables -p input drop
ip6tables -p forward drop 

2001:db8:0000:0000:0000:0000:0000:0001
_____________|____|___________________
network ID   subnet  interface ID

Your router must support IPv6, of course. If you're using a Linux PC as your test machine you're in business. First start IPv6 forwarding:

# sysctl -w net.ipv6.conf.all.forwarding=1

Verify forwarding is enabled:

# cat /proc/sys/net/ipv6/conf/eth0/forwarding
1

A return value of 1 means it is enabled, 0 means it is not. Now install radvd, the router advertiser daemon. Then create /etc/radvd.conf with this simple configuration:

interface eth0
{
   AdvSendAdvert on;
   prefix 2001:db8::/64
   {
   };
};

Copy it exactly, changing only the interface name if necessary. Now create an IPv6 address on your router, or PC acting as your router, and set an IPv6 route:

# ip address add 2001:db8::1a/64 dev eth0
# ip route add 2001:db8::/64 dev eth0

Check your work by running ifconfig and ip -6 route show. Your ip output should look similar to this:

2001:db8::/64 dev eth0 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295
2001:db8::/64 dev eth0 metric 1024 mtu 1500 advmss 1440 hoplimit 4294967295
fe80::/64 dev eth0 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295

Finally, start up the radvd daemon:

# etc/init.d/radvd start

You should now be able to ping the router from another PC. Note that unlike our link-local addresses, we don't need to specify the network interface:

$ ping6 2001:0db8::1a

All of the computers on the same switch as your IPv6 router should have new addresses in the 2001:0db8::/64 range. You can look these up and go on a ping6 frenzy. A default gateway (for connecting to other networks) is the IPv6 address of your router:

# ip -6 route add default via 2001:db8::1a

Of course it's less work to configure it in radvd.conf and have it advertised automatically by adding these lines:

route ::/0
{
};

Then when you run ip -6 route show you'll see this:

default via 2001:db8::1a dev eth0 metric 1024 mtu 1500 advmss 1440 hoplimit 0

What if you don't want radvd blasting IPv6 addresses all over your network? No worries, for you can limit its clients by listing their IPv6 link-local addresses like this:

     interface eth0
     {
             AdvSendAdvert on;
             prefix 2001:db8::/64
             {
                     AdvOnLink on;
                     AdvAutonomous on;
             };
             route ::/0
             {
             };
             clients
             {
                     fe80::20d:b9ff:fe05:25b4;
                     fe80::20b:6aff:feef:7e8d;
                     fe80::221:97ff:feed:ef01;
             };
     };

Mind your braces and semi-colons!