HONG KONG — Anyone who tries to scramble over China’s “Great Firewall” knows the feeling of frustration when those attempts fail. So, too, does the man credited with developing the system, which blocks access to unapproved foreign websites.

That man, Fang Binxing, the former president of the Beijing University of Posts and Telecommunications and current head of a new national industry association for promoting online security, is often called the father of the Great Firewall for his role in developing the system of Internet controls in China. He has previously said that even he has to use virtual private networks, or VPNs, which allow users to gain access to the Internet as if they were in a different location.

During a presentation on digital security on Sunday at his alma mater, the Harbin Institute of Technology, Mr. Fang was forced to employ a VPN when he could not reach websites in South Korea. But the VPN repeatedly dropped out, prompting him to ad-lib some of his presentation.

The episode was relayed by a person who attended the talk and posted details on Weibo and was first reported by the newspapers Oriental Daily News and Ming Pao, both based in Hong Kong. As the story spread online, it prompted widespread mirth among Chinese Internet users who encounter such headaches on a regular basis.