Some of the most useful tools I have found in my port forwarding endeavors are these two websites:
http://www.whatismyip.com/
http://www.canyouseeme.org/
http://www.noip.com/
The first one displays your designated IP, and the second one allows you to check if your ports are open, or in other words, if your attempt to port forward was successful. Please note that
www.canyouseeme.org also now displays your IP address, thus the
www.whatismyip.com website is arbitrary, but still available if you just want your IP.
Go to
www.canyouseeme.org and enter 25565 as the port you want to check. It will tell you whether or not that port is open. If the words are green and you get a message resembling, "
Success: I can see your service on 00.000.000.00 on port (25565) Your ISP is not blocking port 25565." then your ports are open and everyone will be able to join your server. If you get a message like this, "
Error: I could not see your service on 00.000.000.00 on port (25555) Reason: Connection timed out." then your attempt to port forward has failed and you may need to try again.
I would suggest a help video for port forwarding, but every router/modem is different, and the process in which you go about port forwarding will differ based upon your router/modem.
If you get the success message, but people are still having trouble joining your server, I would recommend you double check your current IP address to ensure that your friends have the right one. For reasons I am unaware of, IP's have the ability to change. That was a significant problem for me as my IP was changing daily. To solve this I use
www.no-ip.com. The program converts your 000.000.0.00:25565 to an address such as diablosworld.no-ip.org:25565. This new DNS keeps up with any IP changes you have and your players will always be able to connect to the server.
As for anyone playing on your LAN network. For them to access the server, they must use a separate IP. Their IP will be found on whichever computer is hosting the server. Open up Command Prompt > Type ipconfig > press enter then look for the IPv4 Address. It should look something like 192.168.1.00. Add 25565 to that and you're on your way to success.
If any of my information is incorrect or confusing, please let me know so that I am able to adjust it properly.
