Siemens Simatic RTU303xC Series Operating Instructions Manual page 157

HTTPS
The following settings apply for access via LAN and via mobile wireless.
● Allow only HTTPS access
If the option is activated, connections can only be established to the WBM of the RTU
with HTTPS. Non secure connections with HTTP are not permitted
If you connect to the RTU via an HTTP connection, activate and save this option, the
existing HTTP connection between the PC and RTU can no longer be used. After
activating and saving this option the new HTTPS URL of the RTU is displayed as a link at
the top of the page. Click on the link to remain connected to the RTU without an
interruption.
Note
HTTP connection attempt
If you deactivate the option "Allow only HTTPS access" when an HTTPS connection to
the RTU exists, you must first close the browser and reopen it to be able to connect via
HTTP.
● Enable HTTPS on the WAN interface
Select the option to enable secure communication with the RTU via the internet and the
mobile wireless network using HTTPS. To achieve this port 443 on the WAN interface is
opened.
HTTPS is always enabled on the LAN interface.
Own certificate
In the factory settings the RTU uses a self-issued server certificate for authentication with the
communications partner (client). In the browser of the PC from which you want to connect to
the RTU, in this case a message is displayed when establishing the connection.
Note
Warning message regarding the certificate (HTTPS)
When you establish the connection via HTTPS when you log in a warning message is
displayed indicating that the Web page is unsafe or that the certificate is not trustworthy. If
you are sure that you have entered the correct address, ignore the message. Also add the
connection to the exceptions in your Web browser (depending on the browser).
RTU303xC
Operating Instructions, 06/2019, C79000-G8976-C382-06
Configuration (WBM)
4.16 Security
157