web browser using HTTPS or another user-supplied TLS client. This offloads from the data logger
the intensive computations that are necessary for a TLS server to perform.
Also, with the NL241 configured for TLS, it can establish a secure TLS configuration session with
Device Configuration Utility
.
In order to use TLS, the user must configure the NL241 with a user-supplied TLS private key and
TLS certificate. The key and certificate are loaded using
Device Configuration Utility
.
Using
Device Configuration Utility
, navigate to the Settings Editor tab and then to the TLS tab.
1. Load the user-supplied, PEM-formatted TLS private key using the Set TLS Key button. A file
dialog will open. Navigate to the key file and click Open.
2. Load the user-supplied, PEM-formatted TLS certificate using the Set TLS Certificate button.
A file dialog will open. Navigate to the certificate file and click Open.
3. Enter the TLS Private Key Password if the TLS private key is encrypted. Otherwise, leave the
setting blank.
4. After loading the key and certificate, click Apply. The NL241 will reboot. Connect with
Device Configuration Utility
again and navigate to the Settings Editor tab and then to the
TLS tab. The TLS Status should say Initialized.
NOTE:
The TLS Settings described above cannot be edited over a standard TCP
Device Configuration
Utility
link. The TLS Private Key, TLS Private Key Password, and TLS Certificate can only be
edited/transmitted over a secure
Device Configuration Utility
link (USB or TLS).
NOTE:
If the status of the TLS stack is Initialized, the NL241 will automatically negotiate a secure TLS
connection with
Device Configuration Utility
as long as the Use IP Connection option is
selected.
8.2.6.1 TLS proxy server
A TLS proxy server is a device that acts as a secure intermediary for requests from clients seeking
resources from other servers. A client connects to the proxy server, requesting some service, such
as a file, connection, webpage, or other resource, available from a different server. The proxy
server evaluates the request according to its filtering rules. For example, it may filter traffic by IP
address or protocol. If the request is validated by the filter, the proxy provides the resource by
connecting to the relevant server and requesting the service on behalf of the client.
When the TLS proxy server function is enabled, the NL241 TLS proxy server maintains a secure TLS
connection with a remote TLS client and forwards data to a data logger using a standard TCP
NL241 Wireless Network Link Interface
34
