problem description
the laboratory has a server A, which has applied for a domain name and opened an external network port, which can indeed be accessed outside the school and can be connected through ssh.
I have a computer in my dormitory, which uses the broadband of telecommunications and dynamically allocates ip,. I can also use the routing DDNS, of peanut shell to access my host B.
that is to say, I can use xshell to access both An and B in the company, and the lab server A sometimes can access B. The problem is:
Host B in the dormitory cannot access the server A.
B ping A timed out.
B traceroute An is as follows:
A ping B :
A traceroute B :
ask for advice from the Great God ~