In the campus network, the public network has fixed IP. Why is ss server built and the external network cannot be accessed, but other dormitories can?

  linux, question

Ps, Campus Network Shields Public DNS, Self-built DNS Server

Are you sure it is public network IP? Open ip138 and see if it is the same as your local IP?
Our school used to be a “public network” IP for everyone, which is actually the IP translated from the address. The exit is not this one at all, so the campus can be accessed and the external network cannot be accessed.
There is also a case of real public network IP, but the campus firewall has restricted and shut down all the ports requested by the external network. there is no way to do this. you can try changing the ss port to a common port such as 80, 443 and 8080.