User Documentation

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7.1.2.3 Advanced Settings  Accessible IP List
The Modbus Gateway uses an IP address-based filtering method to control access by itself. The
Accessible IP List function allows you to add or block remote host IP addresses to prevent
unauthorized access.
Example configurations
Example 1 : Only one host with a specific IP address shall access the device
Enter target IP address (e.g. 162.168.1.99) which shall have access
Enter net mask 255.255.255.255 to be the only device (not an IP address range)
Activate checkbox belonging to the address line
Click button Activate
Example 2 : Only hosts of class C network range 192.168.1.0 / 255.255.255.0 shall have access
to the Gateway
Enter IP address range 162.168.1.0 into field IP
Enter net mask 255.255.255.0 to allow access for IP address range 192.168.1.1 to
192.168.1.254
Activate checkbox belonging to the address line
Click button Activate
Example 3 : Any host can access the Gateway
Disable this function by clearing the checkbox 