Our campus network includes three parts: wired network, wireless network and VPN. The campus network export is provided service by four operators: China Telecom, China Unicom, China Mobile, and China Education and Research Computer Network. At present, the campus has basically covered by wireless network, including all dormitories, classrooms, meeting rooms, and part of outdoor public areas. The wireless network's SSIDs mainly includes the following four.

CUHK(SZ): provides Internet services for teachers, students, and faculty members of the school, and can access campus public resources and the Internet.

CUHK(SZ)-GUEST: provides visitors with Internet services, and can access part of the campus resources and the Internet.

CUHK(SZ)-Free: provides Internet services for visitors from great activities or open days.

eduroam: provides Internet services for visitors from scientific research and educational institutions, and can access campus public resources and the Internet. (eduroam supports IPv6 and IPv4 dual stacks. Teachers and students on campus can use eduroam if they need to access IPv6 networks.)

In the office area, classrooms and dormitories are equipped with wired network interfaces, and the wired network supports Gigabit. It is not recommended to use TP-LINK wireless router by yourself. If necessary, please use the pass-through mode without connecting to the WAN port. A VPN is required to access the campus network if not on campus. If you are in China, please enter the server address: vpn.cuhk.edu.cn. If not, please enter the server address: vpnhk.cuhk.edu.cn.

CUHK(SZ) adopts WEB+MAC address authentication. WEB authentication is required only after connecting to the network for the first time and modifying the CUHK(SZ) account password. After that, web authentication is not required for surfing the Internet for 180 days.

Determine whether the network card interface light is normal: If the interface light is not normal, you can use another terminal for testing to eliminate the problem of the terminal network interface card. If the network card and interface lights are normal, please refer to the figure below to check whether the IP address and DNS are obtained normally.

Determine whether it is an AP failure or too many terminals connected to a single AP. If multiple nearby terminals cannot be connected and the AP light is off or flashing quickly, it is generally an AP failure. If there are too many terminals connected to a single AP, switch to another AP or try to connect again later. If the AP displays normal or other users can connect normally, it may be necessary to re-do the WEB authentication.

WEB authentication website: https://wifi.cuhk.edu.cn

If the WEB authentication page cannot be opened, please check whether the IP address and DNS are automatically obtained and assigned normally. The school’s wireless network IPv4 address begins with 10.30. If the IP and DNS cannot be obtained, please change the location or the wireless AP to try to obtain the IP to troubleshoot the terminal.

First, test the internet speed. If you are on campus, please enter: in your browser. This method can be used to test wireless, wired, VPN network speed, etc. Please refer to the figure below for test instructions. If you are not on campus, please enter in your browser: https://www.speedtest.cn/, and select Shenzhen for the speed test node.

The highest negotiation speed of the network card in the wireless network can reach 400 Mbps. For wired and wireless network, the domestic Internet access is 100Mbps downstream and 50Mbps upstream per terminal. (The above values are for reference only.)

The terminal network card model is relatively old. (can refer to the network card to negotiate the speed.)

There are many wireless network terminals under the same IP in classrooms, canteens, and large lecture halls, so the channel occupancy rate is high.

In the dormitories, the AP signal of network is easily obstructed by furniture. You can check whether the AP is obstructed by the cupboard or bed. Usually the wireless signal near the window is weaker.

Wireless network failure.

Wired network port and line quality problems.

Before ensuring that both IP and DNS can be obtained automatically, check whether there is packet loss. You can use the Packet Internet Groper method to observe packet loss and delay. If the packet loss is severe, it indicates that the quality of the access link is poor or the network card itself is faulty. The operation example is as follows:

If some domestic network resources are accessed slow or inaccessible, but can be accessed normally with 4G, it may be due to the limitation of the school's export link or the link needs to be optimized. Please contact ITSO in time.

If these network resources come from overseas websites, they are indeed inaccessible under the current national network security control. Please understand. If these resources come from our university's website or system, they can be resolved using the “three checks” method. ①Check whether the DNS is obtained automatically, if not, please change to obtain it automatically. ②Check whether it is connected to a VPN network outside the university. Please close the VPN network to access the university resources. ③Check whether to use a proxy, if yes, please manually turn off the proxy server, as shown below: