I'd be just as gutted if they ever pull the plug on ipv6.google.com - it's my go-to "first attempt" for an IPv6 test. :-)

But this got me curious, so I grabbed a list of prefixes from [1] and decided to ping them all. Since I went through all that effort, might as well share the findings:

$ for i in `cat list.txt`; do fping -6 $i -t 500 -r 0; done | grep 'is alive'
2409:: is alive
2a09:: is alive
2a11:: is alive
2a12:: is alive
 [<- 2a14:7:ffff::2]2a14:: is alive



[1] https://www.iana.org/assignments/ipv6-unicast-address-assignments/ipv6-unicast-address-assignments.xhtml


Tomas


6. 4. 2024 v 12:00, Ben Cartwright-Cox via NANOG <nanog@nanog.org>:

It appears that 2600:: no longer responds to ICMP.

$ mtr -rwc 1 2600::
Start: 2024-04-06T10:53:41+0100
HOST: metropolis                                  Loss%
 1.|-- lcy02.flat.b621.net                          0.0%
[...]
 6.|-- ldn-b4-link.ip.twelve99.net                  0.0%
 7.|-- ldn-bb1-v6.ip.twelve99.net                   0.0%
 8.|-- nyk-bb2-v6.ip.twelve99.net                   0.0%
 9.|-- ???                                         100.0
10.|-- sprint-ic301620-nyk-b5.ip.twelve99-cust.net  0.0%
11.|-- ???                                         100.0

This seems to have happened around Friday 5th 13:40 UTC.

2600::, a IP address owned by the Sprint network (Now since acquired
by Cogent Communications) is a common (at least in my circles) IPv6
testing address, in a similar way that 8.8.8.8 or 1.1.1.1 is for a
quick address to remember that always pings, when such a address is so
easy to remember, you sometimes cannot help it becoming a "core
project" :) ( https://xkcd.com/1361/ )

2600:: is also used to be the address of sprint.net, now sprint.net has no v6.

This is sad, and I would either propose that Cogent/Sprint (I assume
2600:: is under the ownership of Cogent now) revive this address as
it's a very helpful testing address that is burned into the minds of
many. Or at the very least, I'm more than willing to tank the effort
of responding to ICMP!