**29th October 2018**
^ Talk ^ Speaker ^ Slides ^
|NanoPI M4|Michael Pope|{{ :workshops:20181029-nanopi_m4.pdf |slides}}|
|IP validation, IPtables, and GeoBlocking|Timothy Rice||

===== IP Validation Notes =====
A couple of people asked to have a closer look at Cider, you can find it
at:

https://notabug.org/cryptarch/cider

If you're interested in the Hacker News article which opened my eyes to the
craziness of IP address parsing, you can find it here:

https://news.ycombinator.com/item?id=6580592

Note that the IPv4 spec acknowledges IP addresses in either octet-dot or
unsigned 32-bit integer form:

https://tools.ietf.org/html/rfc791#section-2.3

Thus, the abbreviations from that Hacker News article were not anticipated
and are completely implementation dependent. You can inspect how
implementations can differ by comparing the respective iptables and ipset
interpretations of 127.1/32

For a more recent example illustrating IP addresses in a form that seems
unconventional, these will all take you to a certain popular website:

http://1000849999
http://0x3BA7C24F
http://07351741117

To get started with ipset, this is the Arch Linux wiki article I referred
to:

https://wiki.archlinux.org/index.php/Ipset