force client close connection tcp reset

I have ssh client connect to my server for reverse tunnel.

But sometime the connection idle(I cant ssh to the tunnel(no respond)).
So need to find a way to force client close the connection. (my script on the client will reconnect everytime connection closed)


If I just kill the process on the server, by looking the process id via 'netstat -punat', the process will terminated. But the client does not re-initiate the connection. I believe, on the client side, the process still somehow believe the connection is still on going.
Thus, this not is my attempt to find a solution how to safely force the client to close the connection, so that my script will re-connect back to the server.



First suggestion:
On linux kernel >= 4.9 you can use the ss command from iproute2 with key -K

ss -K dst 192.168.1.214 dport = 49029

  the kernel have to be compiled with CONFIG_INET_DIAG_DESTROY option enabled.

Unfortunately this method is not workable on my server, maybe the kernel no compiled with those features


2nd approach:
Using killcx
On centos:
yum --enablerepo=extras install epel-release
yum install perl-Net-IP

yum install cpanspec


ref: https://unix.stackexchange.com/questions/71940/killing-tcp-connection-in-linux

ref 2: https://superuser.com/questions/127863/manually-closing-a-port-from-commandline/668155#668155

ref3: https://www.tecmint.com/install-perl-modules-using-cpan-on-centos/