On Thu, Oct 17, 2013 at 09:05:24AM -0700, Jason Fesler wrote: > I'm once again considering trying to improve on the test-ipv6.com PMTUD > failure detection. Due to limitations on the client side I can't use raw > sockets to generate test packets. The client is JavaScript and runs in a > browser; all I can do is try fetching urls from multiple locations, each > with a different MTU. > > I know that the various operating systems tend to cache any PMTUD issues > that they can detect; future connections to that destination will use > smaller packets accordingly. What I can not see to find is an adequate > description of what granularity this gets cached with. /128? /64? Also, I > the absence of Packet Too Big messages, what does each OS do?
Linux, too, does cache on /128 basis. In the absence of PTB the connection will get stuck. ;) Greetings, Hannes
