How to deny all ports to a user except one?

Question

linux

You need to make sure that the user has access to only one port.

Answer 1

TCP? USB? port in South America?
either more specifically, and with an example of what has already been done (this is not a freelance, they help here, and do not do the work for you), or be satisfied with the advice "write with a marker on the case - 1 port in 1 hand!"

Answer 2

Question on a specific port of the service or is it a generalized question, about any port?

Answer 3

access to one port - what does this mean in your understanding?
Receive traffic from one port, or send traffic to one port?
Send traffic on one port to any IP?
Accept traffic on one port from any IP?
Accept traffic of one port?
Well, I can write a few more questions.
Specify the statement of TK

Answer 4

policy drop (or reject) for INPUT
and into it - allowing rule

Answer 5

linuxpoison.blogspot.ru/2010/11/how-to-limit-netwo...