Facebook post-mortems...

Tue Oct 5 14:21:16 UTC 2021

* telescope40 at gmail.com (Lou D) [Tue 05 Oct 2021, 15:12 CEST]:
>Facebook stopped announcing the vast majority of their IP space to 
>the DFZ during this.

People keep repeating this but I don't think it's true.

It's probably based on this tweet: 
https://twitter.com/ryan505/status/1445118376339140618

but that's an aggregate adding up prefix counts from many sessions. 
The total number of hosts covered by those announcements didn't vary 
by nearly as much, since to a significant extent it were more specifics 
(/24) of larger prefixes (e.g. /17) that disappeared, while those /17s 
stayed.

(There were no covering prefixes for WhatsApp's NS addresses so those 
were completely unreachable from the DFZ.)

	-- Niels.