> On Jan 18, 2018, at 8:44 PM, William Herrin <b...@herrin.us> wrote: > >> Which packet? Is there a specific CDN that does this? I’d be curious to see >> data vs speculation. > > Howdy, > > Path MTU discovery (which sets the DF bit on TCP packets) is enabled > by default on -every- operating system that's shipped for decades now. > If you don't want it, you have to explicitly disable it. Disabling it > for any significant quantity of traffic is considered antisocial since > routers generally can't fragment in the hardware fast path.
I’m not seeing this in a PCAP capture to at least one CDN, either from my host or from the CDN endpoint. I suspect you’re mistaken. - Jared PCAP: https://puck.nether.net/~jared/akamai.pcap
