So as the title very well explains it. No other computer can even see if the server is online or not. So when its polling it says it cannot reach the server. I have had this server for about 1 month and everybody could connect. So any compute inside my network used the internal ip and any friend outside of the network would just use the external one with the port number. It used to be a vannilla server. So last morning the vanilla server did not work as i mean no one could connect but me using localhost. So I decided to try bukkit. The server now works perfectly when I go on localhost but when it comes to other people no one can even see if the server is online or not. Here is the server.properties file: #Minecraft server properties #Wed Dec 19 14:16:34 AST 2012 generator-settings= allow-nether=true level-name=world enable-query=false allow-flight=false server-port=25565 level-type=DEFAULT enable-rcon=false level-seed= server-ip= max-build-height=256 spawn-npcs=true white-list=true spawn-animals=true snooper-enabled=true hardcore=false texture-pack= online-mode=true pvp=true difficulty=1 server-name=Sicnar Craft enable-command-block=true gamemode=0 max-players=20 spawn-monsters=false view-distance=10 generate-structures=true spawn-protection=16 motd=Sicnar Craft\! Now works on bukkit\! Please could some one help.