Mitsubishi Electric MELSEC-Q Series User Manual page 20

(2) Precautions relating to security
The remote password check function is not designed to completely prevent unauthorized access.
When accessing a CPU module via the Internet, and if it is necessary to maintain the security of the
programmable controller system, the user should take appropriate measures.
Mitsubishi Electric Corporation will not take any responsibility for any system problems that may occur due to
unauthorized access.
Examples of measures against unauthorized access
• Installing a firewall function
• Security measures by the Web server
Take necessary measures by referring to the User's Manual of the device used.
(3) Precautions for accessing the CPU module
(a) When the user creates an ASP or HTML file for the Web function, use the
communication library (QeAccess.dll) provided by Mitsubishi Electric Corporation.
The communication library cannot be created by the user.
For details on the communication library functions, refer to Page 52, CHAPTER 6.
(b) The Web server provides a log function that records file access, etc. Periodically
collect the access log for the programmable controller access file, and check the
access status.
If there are too many unauthorized access logs to the Web server, the user should take appropriate measures
to resolve unauthorized access.
(c) A maximum of four connections are allowed as the simultaneous access count
when accessing the Ethernet module using the Web function.
If this maximum allowable access number is exceeded, a timeout error will be returned from a communication
library function.
In case a timeout error occurs, extend the access interval time and retry.
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