Checking SSL Certifcate on Plesk Mail Server

Run this command (mail.DOMAIN.de is the MX-Record):

SMTP:
openssl s_client -starttls smtp -crlf -connect mail.DOMAIN.de:25

POP3:
openssl s_client -starttls pop3 -crlf -connect mail.DOMAIN.de:110

IMAP:
openssl s_client -starttls imap -crlf -connect mail.DOMAIN.de:143


As result you can see your certificate if it installed correctly:

Certificate chain

0 s:/description=FmJdZEx3lsXPoIXv/C=DE/CN=mail.DOMAIN.de/emailAddress=hostmaster@DOMAIN.de

   i:/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom Class 1 Primary Intermediate Server CA

1 s:/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom Class 1 Primary Intermediate Server CA

   i:/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom Certification Authority

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