use ssh tunnel to connect

A: local machine, can access B

B: ssh server(windows can use openssh for ssh server)

C: A cannot access, but B can

in A, use:

ssh -NfL [A port]:[C IP]:[C port] [B id]@[B IP]

then in A machine you can use localhost:[A port] as [C IP]:[C port]

if B is not a ssh server but have ssh client

you can reverse ssh tunnel

in B, use:

ssh -NfR [A port]:[C IP]:[C port] [A id]@[A IP]