[Solution] Failed to bind to port|Port-forwarding

I have had problems with my server many times. This is the main problem I have. I will be showing you a more detailed way to deal with this server problem.
When you go to run your server before long you are prompted with this message:
What this means is that you have not port-forwarded or you server IP is incorrect.
The first thing you should do is make sure you have port-forwarded.
(I will be showing how to do this, if you would like to skip this, press this)
First you need to identify your external IP. To do this press this.
Once you have your IP, enter it in your search bar.
You will be prompted for your password and username. (By default "Admin" is the username and your router's password will grant you access)
After you have done this you will want to go to something similar to "Applications and Gaming". Once there you will want to click "Port Range Forwarding"
You should then arrive at a page that looks something like this:

You should have only one "Minecraft"
Type in "Minecraft" in "Application Name"
Then open your server.properties file.
Find "port"
By default the port will be "25565" type this in start and end port.
This is where your server might be having its second issue. Some routers will change their IP every time they are shut down or changed. This will cause problems with your server.
To fix this issue and finish port forwarding go to your start menu (Windows)
Type: "Command Prompt"
Open the Command Prompt
Once there you will want to type "Ipconfig"
Press Enter
Once this is done information about your computer and router will come up.
Look for "IPv4 Address"

This is what it should look like. Once you identify your IP address you will want to go back to your Port Range Forwarding page. Type in this IP and check enable.
Save
Once this is done go to your server.properties file.
Type in your IP address once more.
Run your server starter
And you are finished!
Important things to remember:
When your router's IP changes you must change your server.properties file.
Ports on your properties file and router config must be the same.
Other servers can not be running on the same port as your server.

Special Thanks to those who have also suggest these points.
Leaving your server IP blank in server.properties will automatically get your IP. (I might port-forward just so you are able to do it in the future.)
If your router is not the same as mine or does not show the same options press this link. (Thank you shadrxninga)

 

This is good, but there is a few things that you should change:

• Just leave your server.properties file "server-ip=" blank! Minecraft will automatically get your ip and assign the server to it. The "server-ip=" section should only be filled in for special circumstances. For example, if you have more than one ip on the same computer - Useful for hosting companies.
• The "failed to bind to port" error will only happen if you have another server running already on the same port, it doesn't matter whether you have port-forwarded or not.
• Unfortunately - Most people will have a different router to you, and so setup will be different. I suggest adding this link .

 

Another thing that you will need to do is make your IP Static so that your port forwarding always works without going through configuration again. Download this trusty program to change your IP from Dynamic to Static(and vise versa) here.

 

That's not always going to work, your ISP chooses if you have a dynamic or static ip. Contact them if you want to change it. Doing so yourself may cause problems depending on who your ISP is. There is also No-IP, which is very useful - Check it out here.

 

True, true.

 

Strange. On your 2nd point mine is completely different. I have received this when I had nothing else running on the same port.
Will add the other things. Thank you
-Orion

 

The problem with Minecraft, is that the server can be running - and at a glance you would have no idea.

If the error happens again, take a look in task manager and there should be a process called "javaw.exe". This is the server running in the background - end that process and you shouldn't get the error anymore.

 

Of course, your using windows. :/
What about Ubuntu server 10.04 LTS?
I get it and I kill java but it still doesn't work.