1)In Your client machine(LAN)you should have SSH installed
2)In router 'Add service' under Advanced > Port Forwarding
3)Select 

4)In your client machine(LAN)run https service(In browser https://www.google.com)

5)Goto to your external network(WAN),try access ftp server of client machine(ftp -p 192.168.2.30).incoming traffic on ports 21 after seeing an outgoing packet on port 443Common Service as SSH service and Service Type as TCP, then enter Server IPv4 Address where ssh server is installed, port is 22 and save.
4)Try ssh for lan client device using gateway ip address, we should able to access lan client through gateway ip using ssh service.

UDP - The Netcat (nc) command is a command-line utility for reading and writing data between two computer networks. The communication happens using either TCP or UDP

1)In router configure Trigger port 443:443 and Target port 2399:2399Advance > Port Forwarding > Add Service, Common Service as other, Service Name as Netcat and Service Type as UDP, add lan clients's Server IPv4 Address 
2)In Your client machine(LAN)you have to run :  nc -u -l 2399
3)From external WAN machine run nc -u 192.168.2.30 2399 (192.168.2.30 - router router uplink ip address) 
4)In your client machine(LAN)run https service(In browser  https://www.google.com)
5)Goto to your external network(WAN), access server of client machine(Try sending some packets to wan client). Able to see incoming traffic on ports 2399 after seeing an outgoing packet on port 443

1)In router configure Trigger port 443:443 and Target port 5001:5001
2)In Your client machine (LAN)you have to run:  iperf -s -B 10.0.0.106 -i 1 -p 5001 (10.0.0.106 - LAN IP)
3)From external WAN machine run  iperf -c 192.168.161.216 -p 5001 -i  1 -t 60 -B 192.168.160.173 (192.168.161.216 - router uplink ip address, 192.168.160.173 - WAN PC Ip) 
4)In your client machine (LAN)run https service (In browser https://www.google.com)
5)In the WAN PC you will be able to see the traffic and, in the LAN PC, you will be able to see the traffic summery once you stopped the step 3.