You are looking for a free online tool, that checks and test the ssl/tls configuration on a specific custom port, alternative to 443? Then checkout the binsec.tool SSLCheck – there you can specify the port that should be tested, like 8443. The SSLScan fo binsec.tool will give you an overview over the protocols and ciphers of the TLS configuration and checks the level of security. It even supports testing StartTLS for SMTP, IMAP and LDAP.
