I have enabled TLS on my server. I see the log starting tls (STARTTLS). And another domain that we email has enabled TLS on their side. But how do I know that an email I have sent was sent (and received) encrypted using TLS? Here is some of the log written when I send an email to this person.
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: Attempting to Connect: Host MAIL.HUMANSERVICEAGENCY.ORG, Port 25, SSL Port 0, Connecting Domain ntdomino.humanserviceagency.org
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: Connection successful
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 220 mail01.icdn.net ESMTP Postfix (Ubuntu)
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: CommandEHLO: EHLO ntdomino.humanserviceagency.org
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-mail01.icdn.net
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-PIPELINING
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-SIZE 104857600
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-VRFY
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-ETRN
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-STARTTLS
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-AUTH PLAIN LOGIN
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-AUTH=PLAIN LOGIN
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-ENHANCEDSTATUSCODES
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-8BITMIME
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250 DSN
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: CommandSTARTTLS: STARTTLS
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 220 2.0.0 Ready to start TLS
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: CommandEHLO: EHLO ntdomino.humanserviceagency.org
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-mail01.icdn.net
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-PIPELINING
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-SIZE 104857600
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-VRFY
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-ETRN
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-AUTH PLAIN LOGIN
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-AUTH=PLAIN LOGIN
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-ENHANCEDSTATUSCODES
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250-8BITMIME
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250 DSN
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: SMTP Authentication is not required by local server. Username: -blank-
[0A60:0027-0D78] 01/28/2010 01:22:32 PM Router: Transferring mail to domain MAIL.HUMANSERVICEAGENCY.ORG (host MAIL.HUMANSERVICEAGENCY.ORG [63.78.250.11]) via SMTP
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: Attempting to SubmitMessage:
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: Pipelined commands:
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: MAIL FROM:willn@humanserviceagency.org SIZE=9564
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: RCPT TO:Jon.Bonner@k12.sd.us
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: DATA
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: End of pipelined commands
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250 2.1.0 Ok
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250 2.1.5 Ok
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 354 End data with .
[0A60:0027-0D78] 01/28/2010 01:22:32 PM [0A60:0027-0D78] SMTPClient: Data Send Succeeded 9110 bytes
[0A60:0027-0D78] 01/28/2010 01:22:33 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 250 2.0.0 Ok: queued as CB54F2D60C7
[0A60:0027-0D78] 01/28/2010 01:22:33 PM [0A60:0027-0D78] SMTPClient: Attempting to Disconnect:
[0A60:0027-0D78] 01/28/2010 01:22:33 PM [0A60:0027-0D78] SMTPClient: CommandQUIT:
[0A60:0015-0E2C] 01/28/2010 01:22:33 PM Router: Message 006A61E2 transferred to MAIL.HUMANSERVICEAGENCY.ORG for Jon.Bonner@k12.sd.us via SMTP
[0A60:0027-0D78] 01/28/2010 01:22:33 PM [0A60:0027-0D78] SMTPClient: ReceiveResponse: 221 2.0.0 Bye
[0A60:0027-0D78] 01/28/2010 01:22:33 PM [0A60:0027-0D78] SMTPClient: Connection terminated successfully
[0A60:0027-0D78] 01/28/2010 01:22:33 PM Router: Transferred 1 messages to MAIL.HUMANSERVICEAGENCY.ORG (host MAIL.HUMANSERVICEAGENCY.ORG) via SMTP