IPv6 Tunnel

Get a free IPv6 IP from a broker like http://tunnelbroker.net/

Configure the tunnel

modprobe ipv6
ip tunnel add he-ipv6 mode sit remote  local  ttl 255
ip link set he-ipv6 up
ip addr add  dev he-ipv6
ip route add ::/0 dev he-ipv6
ip -f inet6 addr

Check with ifconfig

#ifconfig he-ipv6
he-ipv6   Link encap:IPv6-in-IPv4  
          inet6 addr: fe80::2e26:a772/128 Scope:Link
          inet6 addr: 2001:470:1f08:1a7e::2/64 Scope:Global
          UP POINTOPOINT RUNNING NOARP  MTU:1480  Metric:1
          RX packets:411 errors:0 dropped:0 overruns:0 frame:0
          TX packets:251 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:488490 (477.0 KiB)  TX bytes:22616 (22.0 KiB)

Test ping

# ping6 -c2 ipv6.google.com
PING ipv6.google.com(par03s02-in-x11.1e100.net) 56 data bytes
64 bytes from par03s02-in-x11.1e100.net: icmp_seq=0 ttl=57 time=10.9 ms
64 bytes from par03s02-in-x11.1e100.net: icmp_seq=1 ttl=57 time=10.0 ms
--- ipv6.google.com ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1002ms
rtt min/avg/max/mdev = 10.070/10.512/10.955/0.454 ms, pipe 2

Test website

# curl -6  -v http://sriramrajan.com/status.php
* About to connect() to sriramrajan.com port 80
*   Trying 2001:470:1f08:1a7e::2... connected
* Connected to sriramrajan.com (2001:470:1f08:1a7e::2) port 80
> GET /status.php HTTP/1.1
> User-Agent: curl/7.15.5 (x86_64-redhat-linux-gnu) libcurl/7.15.5 OpenSSL/0.9.8b zlib/1.2.3 libidn/0.6.5
> Host: sriramrajan.com
> Accept: */*
> 
< HTTP/1.1 200 OK
< Date: Wed, 06 Jun 2012 20:34:45 GMT
< Server: Apache
< Vary: Accept-Encoding
< P3P: policyref="http://www.sriramrajan.com/p3p.xml",CP= "NON DSP COR CURa TIA"
< Content-Length: 7
< Content-Type: text/html; charset=UTF-8
ALL OK
* Connection #0 to host sriramrajan.com left intact
* Closing connection #0

#curl -I  -v  -g -k  http://[2001:470:1f08:1a7e::2]/status.php
* About to connect() to 2001:470:1f08:1a7e::2 port 80 (#0)
*   Trying 2001:470:1f08:1a7e::2... connected
* Connected to 2001:470:1f08:1a7e::2 (2001:470:1f08:1a7e::2) port 80 (#0)
> HEAD /status.php HTTP/1.1
> User-Agent: curl/7.21.7 (i386-redhat-linux-gnu) libcurl/7.21.7 NSS/3.13.3.0 zlib/1.2.5 libidn/1.22 libssh2/1.2.7
> Host: [2001:470:1f08:1a7e::2]
> Accept: */*
> 
< HTTP/1.1 200 OK
HTTP/1.1 200 OK
< Date: Sat, 09 Jun 2012 10:35:09 GMT
Date: Sat, 09 Jun 2012 10:35:09 GMT
< Server: Apache
Server: Apache

Check SSH

# ssh -6 -p 2222 2001:470:1f08:1a7e::2
root@2001:470:1f08:1a7e::2's password: 

Firewall
Don't forget the firewall. If you use iptables for a firewall, make sure, you have equivalent setup for IPv6. You can check using

# ip6tables -nvL