Access to the server from the outside, is it possible through a 3G modem?

Question

iptables

Hi all!
There is a server on ubuntu, into which a 3g modem is plugged. It receives the Internet from the modem and distributes through an internal setevushka in a local area (masquerade). Everything works ok.
There was a need to access the server from the outside. And then I ran into a problem.
1) I signed up for the freedns.afraid.org dinds service, before I set it up for a regular non-modem connection in ubunt and everything flew. Now I registered there, and closed up a subdomain like home.site.ru
2) In the site.ru settings, I created a subdomain home, where as ns servers, I registered ns efreid servers. Efreud liked this, and he reported that he was ready to work.
3) To permanently tell the efraud what the server's IP is now, they use a wget script that connects to afraid.org and reports the current IP (by cron). As a result, when I ping the home.site.ru address, I consistently see the correct match name > address. That is, the dindns service worked correctly.
Problem: I can't get into the server via SSH. There is simply no answer. None.
* In LAN with the server, everything is OK, I can easily connect to it on port 22 without any problems.
** When pinging, there is no response from the server, we only see the name>address comparison in the console
*** The reaction is the same directly on the current given gray ip ...
Where to dig gentlemen? server iptables?

Answer 1

You have NAT, you need to contact the operator to get a white IP.
Personally, for a white ip, I had to buy a new SIM card with a special tariff for x5 price
Or use ipv6 tunnels through a broker

Answer 2

Use Teamviewer and GUI )))

Answer 3

The address is grey, you can't access it from outside.
Buy an external VPN or a dedicated address.

Answer 4

In cellular networks, you have a "gray" address. The best option is to set up a VPN server on the equipment available to you, and set it to auto-connect on Ubuntu.
PS: A similar solution was made on Mikrotiks, but the principle is absolutely the same - arxont.blogspot.ru/2014/01/3g.html