SSH into a computer behind NAT

Go to your router settings page, e.g 192.168.1.1
Go to the port forwarding setting page, configure following settings

External Port 2225	Internal Port 22	Protocol tcp/udp	To IP Address 192.168.1.102

You may want to set a normal port, because attacked cannot guess that. If you set 22 to 22, you may have may brute force attacks from outside. Set external port as normal port is more secure. 

Then: 

ssh username(AT)corsairxxv(DOT)gotdns(DOT)com -p 2225

or
scp -r -P 2225 username(AT)corsairxxv(DOT)gotdns(DOT)com:~/work/workspace/ChestTest ~/
scp -P 2225 file.zip corsairxxv.gotdns.com:~/