Yesterday I read this toot (German) over on mastodon which starts with “IPv6 is hard.”

No it’s not. It’s different.

I ran across this multiple times: There is an A and an AAAA-record for a FQDN, but the web server is only reachable via IPv4. You can easily test this with curl

$ curl -4  https://github.com -o /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  273k    0  273k    0     0  3417k      0 --:--:-- --:--:-- --:--:-- 3553k
$ curl -6  https://github.com -o /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
curl: (7) Couldn't connect to server

When using IPv4 273k are “saved” to /dev/null, using IPv6 we get an error message “Couldn’t connect to server”

• CLAT in Linux Networkmanager
• DNS delegation
• jc - Convert command output to json
• Stratoshark - Analyse syscalls
• curl from start to end
• Security Bingo
• Linux Routing Fundamentals
• Packet where are you
• nftable-tracer

The basic Idea: What if we put together an “advent of IPv6” just like – https://adventofcode.com/ or https://tryhackme.com/r/christmas

Gitlab repo including my slides from RIPE89

https://gitlab.com/jenslink/advent-of-ipv6

There is also a mailing list: https://list.sys4.de/postorius/lists/ipv6-advent-orga.lists.quux.de/

You want to make a presentation, write a blog post or document your brand-new software. What do you use as domain-names, IP addresses and AS numbers? If you are documenting your systems or a setup you build for a customer the question is easy to answer: It’s best to use the actual data. But if you are writing a more generic documentation there are some reserved domain names, IP prefixes and AS numbers.