GpsGate can only be reached from localhost
Some info on firewalls
A firewall/router connects to the Internet. This router has a public IP address. And it hides or masks all addresses for the computers on your internal LAN. It is necessary to configure the router/firewall to redirect TCP/IP (and UDP) traffic to the internal IP address of your server. Depending on which GPS trackers you use, you may need to open different ports. You also need to open port 80 for your web server.
You can see your firewall/routers IP address by going to this site:
The IP address you see there. That is the one you should enter in the tracking device configuration.
You can read more about Network Address Translation (masking IP addresses) here on Wikipedia:
Step by step solution
1. Check your public IP address
2. Configure your firewall/router to forward TCP/IP (and UDP) traffic for the port your GPS tracker is using. This is device-dependent, different types of devices uses different ports.
3. Web Server. Configure your firewall/router to forward TCP/IP traffic from port 80 to address your internal IP address on port 80
4. Configure the tracker to send data to the address found in step 1.
Note: please, do not forget to check if you have the Windows Firewall enabled. More info here.