Answer by Dominique for Can I find e-mails, sent over MS-Exchange, using MS-Outlook?

Apparently this is not possible, as the traffic is encoded.

In order to see this, I've done a netstat -aon | findstr 24612 where 24612 is the current process ID of Outlook.exe. This revealed the following:

TCP    10.1.13.317:54626      10.1.6.23:443          ESTABLISHED     24612TCP    10.1.13.317:54700      10.1.6.23:443          ESTABLISHED     24612TCP    10.1.13.317:55190      10.1.6.23:443          ESTABLISHED     24612UDP    127.0.0.1:52573        *:*                                    24612

The port 443 means that "HTTPS" is used, hence the communication is encrypted and can't be read using a sniffer, like Wireshark.