@bortzmeyer

$ sudo apt install ssldump; wget -o /dev/null https://gist.github.com/zachwalton/883b08a2acb6a36177b189977b009593/raw/6adb968bf9f94b3373f725fdd9b9eeb6690152ce/wtftls.bash; sudo bash ./wtftls.bash -i any & openssl s_client -connect www.nouveaufrontpopulaire.fr:443
ssldump is already the newest version (1.9-1).
Summary:
  Upgrading: 0, Installing: 0, Removing: 0, Not Upgrading: 0
[1] 22547
Connecting to 162.159.138.44
CONNECTED(00000003)
40772DFB98740000:error:0A000410:SSL routines:ssl3_read_bytes:ssl/tls alert handshake failure:../ssl/record/rec_layer_s3.c:916:SSL alert number 40
---
no peer certificate available
---
No client certificate CA names sent
Negotiated TLS1.3 group: <NULL>
---
SSL handshake has read 7 bytes and written 1570 bytes
Verification: OK
---
New, (NONE), Cipher is (NONE)
Protocol: TLSv1.3
This TLS version forbids renegotiation.
Compression: NONE
Expansion: NONE
No ALPN negotiated
Early data was not sent
Verify return code: 0 (ok)
---
$ Short read: -6659 bytes available (expecting 2)
Error in TLS connection: handshake_failure [alert code 40]

Reception of a handshake_failure alert message indicates that the
sender was unable to negotiate an acceptable set of security
parameters given the options available.  This is a fatal error.

$ kill %1
[1]  + terminated  sudo bash ./wtftls.bash -i any
$ 
``