On Sun, Apr 18, 2021 at 4:31 PM Matt Corallo <netdev-l...@mattcorallo.com> wrote: > > Should the default, though, be so low? If someone is still using a old modem > they can crank up the sysctl, it does seem > like such things are pretty rare these days :). Its rather trivial to, > without any kind of attack, hit 1Mbps of lost > fragments in today's networks, at which point all fragments are dropped. > After all, I submitted the patch to "scratch my > own itch" :).
Again, even if you increase the values by 1000x, it is trivial for an attacker to use all the memory you allowed. And allowing a significant portion of memory to be eaten like that might cause OOM on hosts where jobs are consuming all physical memory. It is a sysctl, I changed things so that one could really reserve/use 16GB of memory if she/he is desperate about frags. > > Matt > > On 4/18/21 00:39, Willy Tarreau wrote: > > I do agree that we shouldn't keep them that long nowadays, we can't go > > too low without risking to break some slow transmission stacks (SLIP/PPP > > over modems for example).