Siemens SENTRON PAC2200CLP, Product Manual, Page: 59 / 130

Operation
5.4 Protection against manipulation
PAC2200CLP
Equipment Manual, 06/2021, L1V30820585B-02
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5.4.3 Hardware write protection
The hardware write protection prevents write access to the device, both via the
communication interface and on the display.
In order to gain write access, the hardware write protection must be deactivated directly on
the device.
The hardware write protection cannot be deactivated via a communication interface.
To activate or deactivate the hardware write protection, the user is prompted to press the SW
button on the device. The request to do so appears on the display for 15 minutes.
If the SW button has not been pressed once 15 minutes have expired, the change is not
applied and the request message on the device display disappears.
5.4.4 IP filter (subnet firewall protection)
The IP filter, also called subnet firewall protection, is a configurable protection on the device.
If the protection is activated, write requests are only accepted if the user is in the same
subnet.
5.4.5 Modbus TCP port, configurable
Ports are communication channels which make it possible to access a Modbus-capable device
via a network.
Standard IP ports like port 502 are often tested by port scanners. If an open port is discovered
by an attacker, the device can be attacked via this port.
The PAC2200CLP device allows the Modbus TCP ports to be configured manually. Switching
from standard port 502 to a user-defined port makes it more difficult to scan for open ports.