SMTP Connection

I've just installed a docker based instance and am encountering issues configuring SMTP. This instance is from the latest docker containers ( ghcr.io/clearflask/clearflask-server:latest ) or rather a copy from yesterday.

My configuration:

com.smotana.clearflask.core.push.provider.EmailServiceImpl$Config.smtpStrategy=SMTP_TLS
com.smotana.clearflask.core.push.provider.EmailServiceImpl$Config.smtpHost=smtp.sparkpostmail.com
com.smotana.clearflask.core.push.provider.EmailServiceImpl$Config.smtpPort=587
com.smotana.clearflask.core.push.provider.EmailServiceImpl$Config.smtpUser=SMTP_Injection
com.smotana.clearflask.core.push.provider.EmailServiceImpl$Config.smtpPassword=redacted
com.smotana.clearflask.core.push.provider.EmailServiceImpl$Config.emailDisplayName=displayname
com.smotana.clearflask.core.push.provider.EmailServiceImpl$Config.fromEmailLocalPart=noreply
com.smotana.clearflask.core.push.provider.EmailServiceImpl$Config.fromEmailDomainOverride=redacted.com

the container itself (clearflask-server) can connect (have tested with nmap) on the cli. However when the web app tries to connect I see logs such as:

Caused by: javax.mail.MessagingException: Could not connect to SMTP host: smtp.sparkpostmail.com, port: 587 Caused by: javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)

The server requires TLSv1.2 which is not mentioned as disabled in the java.security file and it seems likely this is the correct configuration and a "workable" situation.

openssl s_client -connect smtp.sparkpostmail.com:587 -starttls smtp

Server response snippit:

-----END CERTIFICATE----- subject=CN = *.sparkpostmail.com

issuer=C = US, O = DigiCert Inc, OU = www.digicert.com, CN = RapidSSL TLS RSA CA G1

No client certificate CA names sent Peer signing digest: SHA256 Peer signature type: RSA Server Temp Key: ECDH, P-256, 256 bits

SSL handshake has read 4579 bytes and written 473 bytes Verification: OK

New, TLSv1.2, Cipher is ECDHE-RSA-AES256-GCM-SHA384 Server public key is 2048 bit Secure Renegotiation IS supported Compression: NONE Expansion: NONE No ALPN negotiated SSL-Session: Protocol : TLSv1.2 Cipher : ECDHE-RSA-AES256-GCM-SHA384

An item I see that may be an issue is the wildcard certificate?

I have followed a suggestion from a previous query on this topic and added the following env var to the server container, however am not seeing any related logs.

`JAVA_OPTS="-Djavax.net.debug=ssl"`

I have also followed the email providers suggestions, no joy: https://support.sparkpost.com/docs/faq/smtp-connection-problems

Can anyone provide some additional suggestions for debugging?

Issue #130

ClearFlask