Minecraft Forums

Portforward.com has one of the most comprehensive guides to forwarding ports through variety of routers.

Here is a good place to start: http://portforward.com/help/pfprogression.htm

Also, check your firewall settings to assure the ports are open.

Almost any server you visit will have a set of rules outlined near your spawn point, or in the message of the day. please read these and following the instructions in order to get build permissions.If you cannot locate this information, kindly ask an expert or moderator in the in game chat how to get build Permissions. Usually a whitelist is required.