Siemens SIMATIC S7-1500 Function Manual page 53

Communications services
3.6 Secure Communication
Secure Open User Communication to a mail server (SMTP over TLS)
An S7-1500 CPU can establish a secure connection to an e-mail server with the
communication instruction TMAIL-C.
The system data types TMail_V4_SEC and TMail_QDN_SEC allow you to determine the
partner port of the e-mail server and thus to reach the e-mail server via "SMTP over TLS".
Figure 3-13
Requirement for secure e-mail connection is the importing of the root certificate and the
intermediate certificates of the mail server (provider) into the global certificate memory of the
S7-1500 CPU. By means of these certificates the CPU can check the server certificate that
is sent by the mail server during the establishment of the TLS connection / session.
Proceed as follows to import certificates of the mail server:
1. Open the certificate manager in the global security settings in the project tree.
2. Select the appropriate table (trusted certificates and root certificate authorities) for the
certificate to be imported.
3. Right-click in the table to open the shortcut menu. Click "Import" and import the required
certificate or the required CA certificates.
As a result of the import, the certificate has a certificate ID assigned to it and can be
assigned to a module in the next step.
4. Mark PLC_1 and navigate to the "Certificates of partner devices" table in the "Protection
& Security" section.
5. Click in an empty line in the "Certificate subject" column to add the imported certificates.
6. Select the required CA certificates of the communication partner from the drop-down list
and confirm the selection.
In the next step you have to create the user programs for the e-mail client function of the
CPU and load the configurations together with the program.
52
Secure OUC between a S7-1500 CPU and a mail server
Function Manual, 11/2019, A5E03735815-AH
Communication