1 Problemas de tipo de conexión o permisos

El servidor está configurado para conectarse con PSK al agente, pero el agente solo acepta conexiones no cifradas

En el registro del servidor o proxy (con GnuTLS 3.3.16)

Get value from agent failed: zbx_tls_connect(): gnutls_handshake() failed: \-110 The TLS connection was non-properly terminated.

En el registro del servidor o proxy (con OpenSSL 1.0.2c)

Get value from agent failed: TCP connection successful, cannot establish TLS to [[127.0.0.1]:10050]: \
           Connection closed by peer. Check allowed connection types and access rights

Un lado se conecta con el certificado pero el otro solo acepta PSK o viceversa

En cualquier registro (con GnuTLS):

failed to accept an incoming connection: from 127.0.0.1: zbx_tls_accept(): gnutls_handshake() failed:\
           -21 Could not negotiate a supported cipher suite.

En cualquier registro (con OpenSSL 1.0.2c):

failed to accept an incoming connection: from 127.0.0.1: TLS handshake returned error code 1:\
           file .\ssl\s3_srvr.c line 1411: error:1408A0C1:SSL routines:ssl3_get_client_hello:no shared cipher:\
           TLS write fatal alert "handshake failure"

Intentando utilizar el remitente Zabbix compilado con soporte TLS para enviar datos al servidor/proxy Zabbix compilado sin TLS

En el registro del lado de conexión:

Linux:

...In zbx_tls_init_child()
       ...OpenSSL library (version OpenSSL 1.1.1  11 Sep 2018) initialized
       ...
       ...In zbx_tls_connect(): psk_identity:"PSK test sender"
       ...End of zbx_tls_connect():FAIL error:'connection closed by peer'
       ...send value error: TCP successful, cannot establish TLS to [[localhost]:10051]: connection closed by peer

Windows:

...OpenSSL library (version OpenSSL 1.1.1a  20 Nov 2018) initialized
       ...
       ...In zbx_tls_connect(): psk_identity:"PSK test sender"
       ...zbx_psk_client_cb() requested PSK identity "PSK test sender"
       ...End of zbx_tls_connect():FAIL error:'SSL_connect() I/O error: [0x00000000] The operation completed successfully.'
       ...send value error: TCP successful, cannot establish TLS to [[192.168.1.2]:10051]: SSL_connect() I/O error: [0x00000000] The operation completed successfully.
En el registro del lado de aceptación:
...failed to accept an incoming connection: from 127.0.0.1: support for TLS was not compiled in

Un lado se conecta con PSK pero el otro lado usa LibreSSL o se ha compilado sin soporte de cifrado

LibreSSL no es compatible con PSK.

En el registro del lado de conexión:

...TCP successful, cannot establish TLS to [[192.168.1.2]:10050]: SSL_connect() I/O error: [0] Success

En el registro del lado de aceptación:

...failed to accept an incoming connection: from 192.168.1.2: support for PSK was not compiled in

En la interfaz de Zabbix:

Get value from agent failed: TCP successful, cannot establish TLS to [[192.168.1.2]:10050]: SSL_connect() I/O error: [0] Success

Un lado se conecta con PSK pero el otro lado usa OpenSSL con soporte PSK deshabilitado

En el registro del lado de conexión:

...TCP successful, cannot establish TLS to [[192.168.1.2]:10050]: SSL_connect() set result code to SSL_ERROR_SSL: file ../ssl/record/rec_layer_s3.c line 1536: error:14094410:SSL routines:ssl3_read_bytes:sslv3 alert handshake failure: SSL alert number 40: TLS read fatal alert "handshake failure"

En el registro del lado de aceptación:

...failed to accept an incoming connection: from 192.168.1.2: TLS handshake set result code to 1: file ssl/statem/statem_srvr.c line 1422: error:1417A0C1:SSL routines:tls_post_process_client_hello:no shared cipher: TLS write fatal alert "handshake failure"