Siemens SIMATIC HMI Series System Manual page 65

Observe the following here:
1. The IP address becomes invalid when the network adapter is removed or deactivated after
installation of the TCP/IP protocol.
2. The IP address may not be initialized yet. This occurs, for example, when the TCP/IP
protocol is installed with the IP address derived from a DHCP server. When the computer
is connected to the network, the computer undergoes a basic initialization during which an
IP address is transferred. This IP address then remains valid even after the computer is
disconnected from the network. After the period of the lease has expired, however, it can
become invalid or changed in another way.
If the computer is not connected to the network, the user must log on via a user configured
locally on this computer. This user should have local power user rights for runtime operation
and for the configuration.
Leading zeros in IP addresses
When multi-user mode is used with name derivation via "hosts" and "lmhosts", no preceding
zeros may be entered in the "hosts" file. IP addresses with leading zeros are interpreted as
OCTAL instead of DECIMAL.
Example:
● Computer_1 199.99.99.020 is interpreted as 199.99.99.16 (decimal)
● Computer_2 199.99.99.026 is interpreted as 199.99.99.22 (decimal)
The specification can also be made hexadecimal:
● 199.99.99.0x10 for Computer_1
Using WinCC in multiple domains
The correct functioning of WinCC can only be guaranteed when all the computers in a multi-
user system are located in a common domain or working group. When WinCC is used in
different domains or working groups, complications may arise if the access rights and/or name
utility are configured incorrectly.
When the user administration is realized in a working group, all the WinCC users must be set
up on all the computers in the multi-user system and have the necessary access authorization.
Use of WinCC within a domain
If problems occur accessing the Windows domains, it cannot be guaranteed that WinCC
functions correctly. Therefore, in addition to a "server-stored user profile", a local user profile
and local user with necessary rights for WinCC must be set up. If access problems occur with
a domain logon, exit WinCC and log on again using the local user profile.
WinCC: General information and installation
System Manual, 02/2017, A5E40840020-AA
WinCC Release Notes
2.2 Notes on operation
65