Help with dropping ssh though linux router

[pomtom44]

Hey all
Back again with yet another networking question
 

This time there is the setup
I have a linux router, doing portforwarding using IPtables.
External client logs into internal server using ssh on routers external IP

What im looking for is a graceful way to close the connection
Not block it, just close it.

Currently I am adding a forward drop to the top of the tables list, and that breaks the connection, but it doesn't drop it properly, and as soon as I remove the rule, the connection just pops back up

What im wanting is for when I drop the connection, the client drops properly and has to re connect to the server, rather than just auto connecting 
(If that makes any sense?)
 

And yes I know there is a timeout, (putty will timeout if no connection is made within a certain time), but I want it to work for everything, even if the timeout isn't set on the client side
 

Thanks again for any help, and fingers crossed there is a good way of doing this

[Just.Oblivious]

What is the end goal here?

 

If you want to properly disconnect/end a SSH session you have to do it on the server itself by killing the associated processes.

[pomtom44]

11 hours ago, Just.Oblivious said:

What is the end goal here?

 

If you want to properly disconnect/end a SSH session you have to do it on the server itself by killing the associated processes.

The goal is to be able to end a single ssh session when you dont have access to the server only the router
(Its for a uni project and its easier to just explain it that way)

I have found "Cutter" which seems to do what I want, just is so out of date it wont run on newer linux builds