Server Firewall Troubleshoot (Mac)

[Dredmann]

I have been trying to set up a server just for myself and a few friends to connect to. I port forwarded TCP and UDP port 25565 and I am certain (I have tested) that they are forwarded correctly and are accessible to the public. I have a Verizon FIOS router and I also gave access to the port forward through my router firewall. I could then connect to the server but my friends could not. After many hours of flipping through endless forum posts here and elsewhere and troubleshooting on my own I found that my computer's firewall (not my router's) was the issue (system preferences>security & privacy>firewall). When it is OFF my friends can connect but when it is ON they cannot. Is there an application or program that I can allow through the firewall under "firewall options.." that will let me keep my firewall ON but still allow my friends to connect? I am just not sure what I should be allowing through (Minecraft is already allowed) because the only things related to Tekkit that I can choose from are Unix Files in my Tekkit Server Folder.

Thanks for any help!