Contiki OS running on an ATmega256RFR2 connected via slip6 to mac osx.
sudo ./tunslip6 -B 38400 -s /dev/tty.usbmodem1411 aaaa::1/64
********SLIP started on ``/dev/tty.usbmodem1411''
opened tun device ``/dev/tun0''
ifconfig tun0 inet6 up
ifconfig tun0 inet6 aaaa::1/64 add
sysctl -w net.inet6.ip6.forwarding=1
net.inet6.ip6.forwarding: 0 -> 1
ifconfig tun0
tun0: flags=8851<UP,POINTOPOINT,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::bae8:56ff:fe3d:43a%tun0 prefixlen 64 optimistic scopeid 0xc
inet6 aaaa::1 prefixlen 64 tentative
nd6 options=1<PERFORMNUD>
open (pid 48781)
*** Address:aaaa::1 => aaaa:0000:0000:0000
Got configuration message of type P
Setting prefix aaaa::
Server IPv6 addresses:
aaaa::11:22ff:fe33:4401
fe80::11:22ff:fe33:4401
Pinging from mac osx.
[~]$ ping6 aaaa::11:22ff:fe33:4401
PING6(56=40+8+8 bytes) aaaa::1 --> aaaa::11:22ff:fe33:4401
16 bytes from aaaa::11:22ff:fe33:4401, icmp_seq=0 hlim=64 time=32.370 ms
16 bytes from aaaa::11:22ff:fe33:4401, icmp_seq=1 hlim=64 time=31.145 ms
16 bytes from aaaa::11:22ff:fe33:4401, icmp_seq=2 hlim=64 time=34.833 ms
^C
--- aaaa::11:22ff:fe33:4401 ping6 statistics ---
3 packets transmitted, 3 packets received, 0.0% packet loss
round-trip min/avg/max/std-dev = 31.145/32.783/34.833/1.534 ms