Comment by jcranmer
17 days ago
> After many hours of back and forth with the reporter, luckily a Mozilla employee as well, I ended up buying the exact same laptop, same color, in a desperate attempt to reproduce the issue.
Glad to know that networking still produces insanity trying to reproduce issues à la https://xkcd.com/2259/.
For that matter, a fun read in the "The map download struggle, part 2 (Technical)" section at https://www.factorio.com/blog/post/fff-176 (end of the document).
Factorio's dev blog is a great deal of fun. It's on pause at the moment after the release of 2.0, but if you go through the archives there's great stuff in there. A lot of it is about optimizations which only matter once you're building 10,000+ SPM gigafactories, which casual players will never even come close to, but since crazy excess is practically what defines hardcore Factorio players it's cool to see the devs putting in the work to make the experience shine for their most devoted fans.
This is how I find out there's a 2.0 Factorio? What am I doing with my life??
6 replies →
Could be related to UDP checksum offload.
0x0000 is a special value for some NICs meaning please calculate for me.
One NIC years ago would set 0xFFFF for bad checksum. At first we thought this was horrifyingly broken. But really you can just fallback to software verification for the handful of legitimate and bad packets that arrive with that checksum.
It is funnier if you've ever dealt with mystery packet runts, as most network appliances still do not handle them very cleanly.
UDP/QUIC can DoS any system not based on a cloud deployment large enough to soak up the peak traffic. It is silly, but it pushes out any hosting operation that can't reach a disproportionate bandwidth asymmetry with the client traffic. i.e. fine for FAANG, but a death knell for most other small/medium organizations.
This is why many LAN still drop most UDP traffic, and rate-limit the parts needed for normal traffic. Have a nice day =3