Zend certified PHP/Magento developer

Port forwarding works for friends that have the same ISP as me, but It doesn’t work for anyone with a different ISP?

I’m trying to host a Minecraft server at home for friends, and it’s not going well.

I have done the following:

  • Setup the server
  • Allowed the server through the firewall
  • configured my router to allow port forwarding on the appropriate ports
    My problem: friend 1 is on the same ISP as me, and can connect to my server using my external IP friend 2 is on a different ISP, and cannot connect to my server using my external IP

I’ve made a simple diagram to hopefully demonstrate my problem:
image
Am I doing something wrong? I have little to no idea what I’m doing. if you need anymore info let me know. 🙂