Exactly as I expected. For you to be able to provide any kind of server the standard way, you have to have public IP address as your second hop. In the output of this command, your first IP address is 192.168.31.1 and your second is 10.161.115.1
The ranges for private addresses is:
- 10.0.0.0 to 10.255.255.255
- 172.16.0.0 to 172.31.255.255
- 192.168.0.0 to 192.168.255.255
Your first IP is from range 192.168. and to have public IP, your second IP has to be not from private range, yet is says 10.x.x.x so you really need to contact your ISP and explain, that you would like to have a server, so you need public IP - not to be behind double NAT.