Since migrating to OpenSSL 3.0 we are experiencing intermittent issues
in TLS handshakes.

Old env: Ubuntu 21.10 / Postfix 3.5.6 / OpenSSL 1.1.1l
New env: Ubuntu 22.04 / Postfix 3.6.4 / OpenSSL 3.0.2
(daily updated to latest available patches)

Narrowed this down to Java / JavaMail clients connecting to the Postfix service.

Network trace shows that any time Postfix responds to a ClientHello
containing a SessionId with a ServerHello with session_id_length = 0,
the client returns a a Fatal alert, unexpected_message.

See also
 * https://github.com/openssl/openssl/issues/18690
 * https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1012799

Will also (try to) report this to the Ubuntu folks

With kind regards,
Bernard Spil
[email protected]

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