IPv6 is a lot less complicated that you think.
Once you get past the hex codes and once you see that basic concepts and tools are similar, you’re in good shape to start using it.
How to Ping
One of the most complicated things if you’ve never worked with IPv6 is to use the PING command. To use the ping command under most circumstances, you may need:
- To use the
ping6command instead ofping - An IPv6 enabled workstation or an IPv6 website to ping from
- Specify the interface from which to ping
The second point is important, because under some circumstances if you ping and IPv6 address you might get Invalid Argument like below:
ping6 fe80::88e9:97ff:fec3:aae0 PING fe80::88e9:97ff:fec3:aae0(fe80::88e9:97ff:fec3:aae0) 56 data bytes ping6: sendmsg: Invalid argument
The solution is to specify a % and the interface name, for example:
ping6 fe80::88e9:97ff:fec3:aae0%ens18
How to add a default IPv6 Route
Example:
ip -6 route add default via 2620:1e6:101::8888:1 dev venet0
How to Determine the Default IPv6 Route
Normally on Linux to determine the default route you may use ip route or netstat -rn
The equivalent for IPv6 is ip -6 route
What is a /64?
“There are 2^128 or 340 trillion, trillion, trillion IPv6 addresses, which is more than 100 times the number of atoms on the surface of the Earth. This will be more than sufficient to support trillions of Internet devices for the forseeable future. So in answer to your question, we don’t need to subnet like we did for IPv4. We subnetted and used NAT as a workaround because we didn’t have enough addresses before. Using /64 should always be fine. We will destroy the earth or kill ourselves before we run out.”
See https://stackoverflow.com/questions/15265893/what-does-it-mean-64-in-ipv6 and http://www.steves-internet-guide.com/ipv6-guide/
Caveats
Shared Hosting Control Panels
A notable caveat on some Linux control panels, e.g. Virtualmin, is that there is a separate firewall for IPv6. In fact, that is also the case when you are using cloud providers such as AWS. So be careful! Your server might be Fort Knox for IPv4, but an intruder could come in via IPv6.