>> Would something like this help? >> (borrowed from https://en.wikipedia.org/wiki/Path_MTU_Discovery) >> >> "Many network security devices block all ICMP messages for perceived >> security benefits, including the errors that are necessary for the proper >> operation of PMTUD. This can result in connections that complete the >> TCP three-way handshake correctly, but then hang when data is transferred. >> This state is referred to as a black hole connection." > > Yes. What we are asked to do for Internet Standard is show that a protocol > is widely deployed and is interoperable. That's undoubtedly true of RFC1981. > The fact that it also has an important failure mode should certainly be > documented, but I suspect that every Internet Standard has at least > one important failure mode. the problem is that this particular failure mode is essentially "does not work on the real internet." perhaps documenting that is useful. but i guess this is ipv6. randy