Hello
I have MailEnable premium installed on my server, and need to implement SSL certificate in order to use it with SMTP connections as usual.
After implementing the certificate to IIS and setting it in MailEnable server configurations, I couldn't connect to the server via secure connection using TELNET for example, instead of that I only get a black screen in CMD after calling telnet command on the port 587 enabled with SSL certificate.
You can try that like this:
telnet 52.255.201.160 587
If you try telnet with port 25 and (EHLO) command you can see STARTTLS supported in commands.
Any help with this issue?
Thanks.
Problem with SSL certificate and SMTP connection
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Re: Problem with SSL certificate and SMTP connection
If you have configured an SSL port for a service, you will only get a black screen when you use Telnet to connect to it. So it is indicating it is likely working. To test SSL ports you are best to use something like OpenSSL, which gives you a lot of ability to diagnose connections, make sure they are TLS 1.2, etc.
For example, you can check if a port is TLS 1.2:
openssl s_client -tls1_2 -connect 127.0.0.1:587
Or check STARTTLS works:
openssl s_client -starttls smtp -tls1_2 -connect 127.0.0.1:25
For example, you can check if a port is TLS 1.2:
openssl s_client -tls1_2 -connect 127.0.0.1:587
Or check STARTTLS works:
openssl s_client -starttls smtp -tls1_2 -connect 127.0.0.1:25
Re: Problem with SSL certificate and SMTP connection
I found this site very helpful in confirming that SSL and TLS are set up correctly. Found a few bugs the first time I used it.
https://www.checktls.com/TestReceiver
Click on the "More Options" to select a different port etc...
https://www.checktls.com/TestReceiver
Click on the "More Options" to select a different port etc...