On Mon, Sep 2, 2019 at 8:13 PM David Ahern <dsah...@gmail.com> wrote: > > On 9/2/19 4:07 PM, Dave Taht wrote: > > Windows has the "RtmGetMostSpecificDestination" call: > > https://docs.microsoft.com/en-us/windows/win32/rras/search-for-the-best-route > > > > In particular, I wanted to search for the best route, AND pick up the > > PMTU from that (if it existed) > > for older UDP applications like dnssec[1] and newer ones like QUIC[2]. > > RTM_GETROUTE with data for the route lookup. See iproute2 code as an > example.
Yes. I really didn't describe my thinking very well. It's coping with pmtu better in the case of a more increasingly udp'd and tunneled internet. tcp (being kernel based) will do the probe and cache that attribute of the path, udp does not. A udp based app with root privs could be setting it after figuring it out, a userspace one cannot. for more detail from server-al sides of that philosophical debate, please see the links I posted originally. -- Dave Täht CTO, TekLibre, LLC http://www.teklibre.com Tel: 1-831-205-9740
