How to debug a TLSv1.3 protocol problem?

Matt Caswell matt at
Wed May 20 15:08:39 UTC 2020

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.


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