Openssl

Debug

Example when debugging a tls connection to mosquitto MQTT broker.

root@beaglebone:/home/debian# openssl s_client -connect 127.0.0.1:8883
CONNECTED(00000003)
Can't use SSL_get_servername
depth=0 C = DK, ST = Denmark, L = Viborg, O = Mercantec, CN = beaglebone.localdomain, emailAddress = heth@mercantec.dk
verify error:num=18:self signed certificate
.....

On Mosquitto brokerside:

root@beaglebone:/home/debian# /usr/sbin/mosquitto -c /etc/mosquitto/mosquitto.conf -v
1621664904: mosquitto version 2.0.7 starting
1621664904: Config loaded from /etc/mosquitto/mosquitto.conf.
1621664904: Opening ipv4 listen socket on port 1883.
1621664904: Opening ipv6 listen socket on port 1883.
1621664904: Opening ipv4 listen socket on port 8883.
1621664904: Opening ipv6 listen socket on port 8883.
1621664904: mosquitto version 2.0.7 running
1621664907: New connection from 127.0.0.1:45026 on port 1883.
1621664907: Sending CONNACK to 127.0.0.1 (0, 5)
1621664907: Client <unknown> disconnected, not authorised.
1621665067: New connection from 127.0.0.1:54532 on port 8883.
1621665067: OpenSSL Error[0]: error:14094418:SSL routines:ssl3_read_bytes:tlsv1 alert unknown ca

Error 14094418 - alert unknown ca

openssl errornumber to errorstring: (Just nice to know)

root@beaglebone:/home/debian/certs/ca# openssl errstr 14094418
error:14094418:SSL routines:ssl3_read_bytes:tlsv1 alert unknown ca