Paul Vixie <p...@redbarn.org> wrote: > > happily, that's not known about PLPMTUD (RFC 8899 & 8900). so right now > there's new hope, yet undashed.
I'm trying to understand how PLPMTUD can help the DNS. The DNS doesn't have a paketization layer as such - any time the DNS needs to get a big message over a pipe that's too narrow, we get TC and fallback to TCP which does the packetization for us. My very superficial understanding is that PLPMTUD is based on application-level probe / timeout / retry instead of ICMP errors. DNS resolver implementations have machinery to probe the largest working EDNS buffer size, so we already have something in the same ballpark as PLPMTUD. For me the questions are: * what's the hard ceiling on a resolver's EDNS buffer size? * what's a resolver's starting probe buffer size? * how complicated is the resolver's probe algorithm? * what's the ceiling on an auth server's UDP response size? Tony. -- f.anthony.n.finch <d...@dotat.at> http://dotat.at/ Dover, Wight: Northeast 5 to 7. Moderate. Fair. Good. _______________________________________________ dns-operations mailing list dns-operations@lists.dns-oarc.net https://lists.dns-oarc.net/mailman/listinfo/dns-operations