Problems with Tekkit server?

Yesterday I made my tekkit server. My port has been forwarded and the ip to the server is my ip so I know it works. Also, a few of the thing i put in the server properties i noticed actually happened. So my server is fine and all but for some reason my friends are having connection problems. They keep getting connection timeout or end of stream. But one of my friends has a minecraft server so he might be able to help me. Any help?