Depending on the system you’re documenting, you may find you need to include example IP addresses either in text or screengrabs at some point. Including real-life data from the docs/test system could leave the company you’re working for exposed to attacks, as a malicious reader may (often rightly) infer that the system used for documentation uses weak passwords, may contain development versions of software with buggy areas, and probably isn’t policed for odd looking behaviour. Continue reading “IP Addresses in Documentation”
Tag: IPv6
Happy World IPv6 Day!
June 8, 2011 has been designated World IPv6 day – a day when lots of the big players on the internet have committed to switch on and test IPv6 for a day to see how it goes. Hopefully, it’ll go swimmingly and no-one will be turning it off again later.
So what is IPv6, and why does it deserve its own day?
IPv6 stands for “Internet Protocol, version 6” and is the latest standard for assigning addresses to internet-capable devices.
Some History – IPv4
Before IPv6, machines on the internet were given addresses using IPv4. IPv4 addresses were 32 bits long, typically written as four decimal numbers, up to 3 digits long each, separated by decimal points. For example:
192.0.2.1
This gives ~4.3 billion unique IPv4 addresses to serve a current world population of ~6.9 billion. (I’m using US billions here.) Although back in the day when someone reckoned there was a world market for 5 computers this might’ve seemed excessive, now that many of us own a variety of internet-capable phones, computers/laptops, games consoles, even home electronics, and big businesses have farms of thousands of servers, it really doesn’t cut it any more.
ICANN (the Internet Corporation for Assigned Names and Numbers), who are responsible for managing internet address space, handed out the last of the IPv4 addresses to the 5 World RIRs (Regional Internet Registries) on February 3rd, 2011. Once these addresses are handed out, that’s it for IPv4 unless unused addresses can be reclaimed from their current owners – and would you willingly part with a resource that rare?
In practice, there are lots of tricks people use to allow machines to re-use a selection of IPv4 addresses, but reusing address prohibits these machines from communicating directly with each other – instead they usually hide behind and communicate through other machines that do have precious, unique addresses.
The Future – IPv6
So how about IPv6 addresses? These are 128 bits long, written as 8 hexadecimal numbers, up to 4 digits long each, and separated by colons. For example:
2001:0DB8:0000:0000:0202:B3FF:FE1E:8329
This gives a grand total of 3.4×1038 addresses, equating to significantly more than billions of trillions of addresses per person on the planet. Nice! Lots of scope there for an ever more internet-connected life for us all, if you’re into that kind of thing, and I am. 🙂
Want to Know More?
If you want to know more about IPv6 and its implementation, my hubby, David Malone, is co-author of this excellent O’Reilly volume, along with Niall Murphy (no relation): IPv6 Network Administration.