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
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!!
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 :)
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dns question I'm having trouble googling the answer to: why do MX records have a priority (like '10 aspmx.l.google.com.')? like A records and NS records also have multiple servers, but they don't have a priority
I'm not going to do this but sometimes I think about writing a book called "networking for millennials" which explains which networking things still make sense today and which ones made sense historically but are kind of outdated given how we design infrastructure now
computer language poll: is mail.google.com a subdomain of google.com? (not a trick question, no wrong answers, please don't argue about it in the replies, I'm just curious what different people think the word "subdomain" means :) )
the ambiguity here is that mail.google.com doesn't have its own NS/SOA record. An example of a subdomain that *does* have those things is alpha.canada.ca -- it has a different authoritative DNS server than canada.ca does.
anyway I think arguing about definitions of words is super boring but I always think it's interesting when a really common technical term has multiple meanings (so far 6% of people definitely voted no to that poll! :))
here's a fun open source story! i wrote a ruby profiler called rbspy 3 years ago. when I started the project, segiddins filed an issue asking for C functions to be profiled correctly (github.com/rbspy/rbspy/is…). I spent some trying to fix it but never figured out how to do it (1/2)
and then just last week, acj wrote a beautiful pull request that fixes the issue github.com/rbspy/rbspy/pu…! It uses a method of resolving the C function names that I didn't know was possible! It was so fun to get to see how it works and we merged it yesterday. (2/2)
maintaining an open source project is boring sometimes (like when you're redoing your CI again!) but I really love learning from other people's contributions to the project
does anyone know a clear explanation of **exactly* what happens when you send a packet to 8.8.8.8 from a docker container? (i *think* the packet goes out through the veth pair, gets SNAT-ed, and comes back through the docker0 bridge but I'm very confused about it)
found this great blog post thanks to @vaijab that shows how to trace a packet's journey with `perf trace` and I'm so happy right now blog.yadutaf.fr/2017/07/28/tra…
also I think this post by @iximiuz is the clearest explanation of container networking I've ever read (though it still doesn't feel simple to me :) ) iximiuz.com/en/posts/conta…
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