Thread by @b0rk

something I don't understand about BGP: can I (as a Regular Person with no special privileges) actually look up past BGP route announcements to see where facebook withdrew its BGP routes? how/where do I do it?

I now have links to a lot of tools but I still don't really understand how to use/interpret them, I feel like I need a screencast of someone explaining how to use one of these tools to look at this facebook issue :)

like this BGPlay interface is not that intuitive. maybe 129.134.30.12/24 is the wrong subnet and I should be looking at something else?

ok I think I understand it better thanks to this tweet! it's much easier to look at the route announcements right before / right after all the routes were deleted because it's a lot less messy

https://twitter.com/Nayfield/status/1445135144730472456

I think I found one of the first route announcements after all the routes were deleted

i already learned something new which is that apparently a BGP route announcement can have more than one AS in it (like 31313 3356 1299 32934 is romania -> level3 -> telia -> fb). I don't really understand who's announcing that though, like is fb announcing a route from romania?

is there an easy way to find out which bgp route(s) i'm personally using to get to facebook.com?

traceroute -A is really cool! I had no idea traceroute could shows me the AS of everything on the path!!

https://twitter.com/jonahedwards/status/1445209276134223873

i might try to write a blog post about this later -- I've been really hesitant to write/learn about BGP because it's harder to experiment with (I have no way to publish BGP routes and maybe I never will!), but it seems like it's possible to at least view some routes!

i still don't understand how mtr / traceroute map an IP to an AS

i'm very happy to have learned some ways to poke at BGP, I found all the BGP explainers I read to be very frustrating because none of them told me how to actually DO anything with BGP, it was all abstract :)