Nobody can connect!

I did everything right i did it twice but when i give my friends the ip none of them can connect i even tried my brother that live with me and he cant can someone help.

 

You probably aren't using the correct ip address

 

what ip do i use

 

Have you port forwarded?

 

The IP you use depends on who is connecting, if it is someone in your house, you use the internal IP (192.168.x.x/10.0.x.x, eg). If it is someone outside of your house, you give them the external IP, which can be found here.

Also, ensure you have port forwarded correctly, go to http://www.canyouseeme.org/, type in the port you set to your Bukkit server and check it, if it returns a "Success: I can see your service", you are fine, but if it shows "Error: I could not see your service" then there is a issue with either;
A) Your port forwarding
B) A 3rd party program is blocking it (Anti-Virus, Firewall)