The reason why NTHU's IP address 140.114 or domain nthu.edu.tw is not white-listed is due to occasional issues with spam bots. Most spammers will fake messages sent by NTHU. This will expose all of our e-mail users to spam. Therefore, it is not suitable to white-list the all the university's IP addresses; only properly managed server IPs are added.
We advise users to decide on customized black and white lists (email or IP) that suit their needs, or report missed spam or normal mail that was blocked to the vendor, and new filters rules will be updated after analysis is complete to increase the accuracy of spam blocking.