Pilot CUHK VPN Add-On Service for Online Teaching and Learning Activities - Updates on Oct 8, 2020


  • Unstable CUHK VPN connection reports have been received from users in Mainland China starting Oct 1, 2020
  • This article aims to provide an overview of the current status and some workaround identified for the moment.


  • For the VPN server address vpn.cuhk.edu.hk, and, reduced number of connections from China was observed

CUHK VPN (with Add-On Service supported by Huawei Cloud)

  • VPN connection still can be established by using VPN server IP or
  • Multiple retries might be needed before connecting successfully

Common issue (1)

  • Server no response error (windows)

  • Press windows key + R, type “regedit” to run

  • Check and verify in


Value for ProhibitIpSec should be 0


Value for AssumeUDPEncapsulationContextOnSendRule should be 2

Reboot the machine and try again if the value in Windows Registry changed.

Common issue (2)

  • Credentials error:

  • Please make sure your credentials are accurate,
    and then try to login with password in the form of "[OnePass],[DUO 6digit token]",
    please be noted that there is a comma in between,

Alternative services

  • Besides the L2TP/IPsec CUHK VPN solution above, you may also consider the following to access some of the learning materials in the internet.

Alternative service (1): CUHK SSL VPN

  • CUHK SSL VPN for CUHK network restricted website, https://www.itsc.cuhk.edu.hk/all-it/wifi-and-network/ssl-vpn/
  • This is a split tunneling solution i.e. only CUHK network website will go through this VPN,
    while other destination e.g. google, twitter remain using original ISP route.
  • It can help you to access CUHK services requiring a CUHK VPN connection.

Alternative service (2): Third Party VPN (supported by HKT)

  • Third Party VPN for non-China hosted eLearning website (blackboard), you may contact kaze@cuhk.edu.hk for using this solution.
  • This is a China hosted VPN service provided by a third-party vendor (HKT).
  • No Google. No YouTube. Sites which are blocked by the PRC are still blocked.
  • It can help you to access Blackboard, Panopto, CUHK Library (open access catalog).