On 20/05/2020 14:24, Claus Assmann wrote: > On Wed, May 20, 2020, Matt Caswell wrote: > >> I wonder if there could be some middlebox in between these two peers >> that is interfering with the connection in some way and arbitrarily >> closing it down? > > No, it's being tested on localhost. And it works fine if I use a > different server (e.g., openssl s_server) or a different client, > i.e., it is (so far) only this specific combination (M1 -> S8) > which does not work. > Can you test the underlying socket to see if it has been closed down in an orderly way (i.e. recv() should return 0 on the socket if so)? That would confirm or deny the EOF theory. Matt