Why is the local server not visible from the Internet, although the ports are forwarded, what is the error?

Question

Computer networks

Good time.
There is a local server on port 1596, it opens on the local machine at the address localhost:1596, and from any computer on the network at the address of the computer on which it is installed and the corresponding port (192.168.1.11:1596).
It is necessary for test purposes to make it available from the Internet, i.e. at the address *** my white IP from the provider ***: 1596 The
Internet is connected via an ADSL modem (192.168.1.1), to which a router (192.168.1.2) is connected, which distributes the Internet to 4 computers via cable and mobile devices via WIFI.
I forwarded the port on the modem according to the manufacturer's instructions ( www.dlink.ru/ru/faq/160/139.html), and when checking NMAP it shows that everything is working.
Scan report - https://suip.biz/en/?act=report&id=90aa40e818612e0...
Starting Nmap 7.50 ( https://nmap.org ) at 2017-06-23 14:09 MSK
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 15.74 seconds
On the modem forwarded port 1596 to the router ( 192.168. ) already to the local server 192.168.1.11.
It is right? Or is it necessary directly from the modem to the local server?
However, I tried to add such a rule - nothing changes.
Please tell me where to look for the error? What data to provide?
As I understand it, I have a problem somewhere locally, and my white external IP itself is visible from the Internet normally. I understand from nmap. Or I'm wrong?

Answer 1

For good - enable dhcp on the modem, configure the distribution of addresses as on a router, and from it port forwarding to the target machine. Switch the router itself to switch mode (disabling dhcp on it) if the modem does not have the required number of lan ports. Such a scheme will work stably.

Answer 2

Double forwarding will also work quite well if it is done without errors. Most likely a typo in ip addresses or port.