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Verify TLS Exchange communication


I would like to know a fool proof way to verify if my exchange server 2007 is communicating with another domain over TLS.

If anyone in my LAN sends an email using my exchange to xyz.com, how can I verify if the mail was sent over TLS?

Thank you.
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1 Solution
Hypercat (Deb)Commented:
You can look at the SMTP Send logs and search for the xyz.com domain.  If TLS is being used, you'll see the related communication in those logs.
netcmhAuthor Commented:
Can you give me a step by step? I'm not the mail admin. He's out and I'm tasked with the work.
netcmhAuthor Commented:
I dug around a bit. So, in the Exchange Management Console, I chose Message Tracking under Toolbox.

Then, I put in the recipient, the eventid as send and chose the start and end dates; and hit next.

I see a whole bunch of email logs and I'm going to go out on a limb and say that the recipientStat is the column I'm supposed to look at, as it has the 250 2.1.5 ok status. I think the 250 is the indicator that TLS is being used.

Please let me know if I'm way off base, and where else I can check to see if this domain is actually configured as a TLS communicator.
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Hypercat (Deb)Commented:
First, you have to make sure that your Send connector is set to Verbose logging.  The easiest way to do this is to open the Exchange Management Console/Organization/Hub Transport and look at the properties of the Send Connector. On the General tab there is a drop-down to set the logging level. There are only two options, None and Verbose.  If it's already set to Verbose, then you're good.  If it was set to None, then you need to change it to Verbose, restart the Transport service, and do a test email to that domain to generate the log entries.

The SMTP Send protocol logs are by defaulte located in the following folder:

C:\Program Files\Microsoft\Exchange Server\TransportRoles\Logs\ProtocolLog\SmtpSend

However, your Exchange admin could have moved these folders, so you might have to search around to find them.  The logs can be opened in any basic text editor.  Once you have the log open, then search for the domain name until you find an email being sent to that domain.  The specific log entries you're looking for are similar to this:

2013-11-13T00:22:02.381Z,External SMTP Connector,08D09BAD42D08496,12,,,<,250-STARTTLS,
2013-11-13T00:22:02.381Z,External SMTP Connector,08D09BAD42D08496,13,,,<,250 DSN,
2013-11-13T00:22:02.381Z,External SMTP Connector,08D09BAD42D08496,14,,,>,STARTTLS,
2013-11-13T00:22:02.412Z,External SMTP Connector,08D09BAD42D08496,15,,,<,220 2.0.0 Ready to start TLS,
2013-11-13T00:22:02.412Z,External SMTP Connector,08D09BAD42D08496,16,,,*,,Sending certificate
2013-11-13T00:22:02.412Z,External SMTP Connector,08D09BAD42D08496,17,,,*,"CN=[your server FQDN], OU=Domain Control Validated",Certificate subject
2013-11-13T00:22:02.412Z,External SMTP Connector,08D09BAD42D08496,18,,,*,"SERIALNUMBER=07969287, CN=Go Daddy Secure Certification Authority, OU=http://certificates.godaddy.com/repository, O=""GoDaddy.com, Inc."", L=Scottsdale, S=Arizona, C=US",Certificate issuer name
2013-11-13T00:22:02.412Z,External SMTP Connector,08D09BAD42D08496,19,,,*,2798C66B88BB77,Certificate serial number
2013-11-13T00:22:02.412Z,External SMTP Connector,08D09BAD42D08496,20,,,*,5112EB98C90808FFA84C1D5EE79A2442A450615F,Certificate thumbprint
2013-11-13T00:22:02.412Z,External SMTP Connector,08D09BAD42D08496,21,,,*,[list of valid server FQDNs for your certificate],Certificate alternate names
2013-11-13T00:22:02.506Z,External SMTP Connector,08D09BAD42D08496,22,,,*,,Received certificate
2013-11-13T00:22:02.506Z,External SMTP Connector,08D09BAD42D08496,23,,,*,2A2E9B5C7B49EB536F69D84BECB1724AFB003BEE,Certificate thumbprint
Hypercat (Deb)Commented:
No, the 250 only indicates that the communication was successful.
netcmhAuthor Commented:
Thank you. Where else I can check to see if this domain is actually configured as a TLS communicator?
Hypercat (Deb)Commented:
By default, on the sending side Exchange 2007 will use what is termed "opportunistic TLS."  This means that if an external server requests that the communication be encrypted, the Exchange 2007 server will respond by sending the SSL certificate information and encrypting the communication.  You set the options for receiving email in the properties of your Receive Connector(s), on the Authentication tab, or by using the Exchange management shell. In both cases, you have the option to select to use TLS opportunistically (the default) or MutualAuth TLS, which requires TLS to be enabled on both ends and will reject email that is not encrypted.

Here's a link to some Technet info on TLS if you want more info:


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