I recently made a server. I can connect to it just fine (I've had no problems so far). However, when my friends try to connect, in their sever list it says that it can't reach mine. I have allowed Minecraft_Server.exe through the firewall, and have also given my friends the ip needed to connect.
OS: Windows XP SP3
RAM: 504 MB RAM
Processor: Intel Pentium 4 @ 2.8 GHZ
Internet speed: Usually around 10 Mbps for download, around 1.5 Mbps for upload.
Router: AT&T 2Wire 3800HGV-B
IP used to connect: 220.127.116.11