User Documentation

OPC UA Server
System manual
2696790000/02/04.2020
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Free and licensed OPC UA clients are available on the Internet for testing
the functionality of the OPC UA Server. The endpoint URLs of the OPC UA
Server returned by the Discovery service always contain the host name of
the controller. The OPC UA Client must be able to resolve the host name
when connecting to the Server IP (e.g. via host file or DNS).
Information
The host name must never begin with a digit, otherwise problems may oc-
cur during server boot-up or connection setup.
If the Discovery service returns an error code, there is either a network prob-
lem or it was not possible to start the server correctly. More detailed error
sources can be found in Server Logging, see 11.6 Logging of server opera-
tion.
If the OPC UA Server finds expired licenses or no licenses at all during the
connection setup (ActivateSessionRequest), the OPC UA error code
BadLicenseNotAvailable is returned. It is not possible to set up a connec-
tion.
The OPC UA Server supports the following connection types:
● Unencrypted connection
● Encrypted connection via certificate
Unencrypted connection
If unencrypted connections have been configured at the time of installation,
the OPC UA server can be accessed with the OPC UA client via an unen-
crypted connection. The registration can be done anonymously or by user-
name and password. An anonymous client has full access to all nodes and
network data.
In the user administration the user "Administrator" is created with the pass-
word "tobechanged" as standard. The OPC UA Server accepts all users cre-
ated in the user administration.
Information
The use of an unencrypted connection during operation is strongly advised
against as this represents a major security risk due to possible unautho-
rized access. The unencrypted connection should therefore only be used
for development purposes.
Encrypted connection
With an encrypted connection, both OPC UA Server and OPC UA Client
must authenticate each other. This is done via a "public-key" procedure us-
ing certificates. Basic256Sha256 (Sign, Sign & Encrypt) is used as the en-
cryption algorithm. (For further literature on the certificate mechanism, see
e.g. OPC Foundation Website.)