Ahh okay, sorry i didn't respond back sooner just noticed a new post now. Anyway check your configurations for the server. If it checks out green, could be something on your end, in the actual server configurations. I use Bukkit, so its a bit easier for me to use. But more so, the configurations file.
http://minecraft.gamepedia.com/Server.properties
Basically edit your server.properties file, and change your port to the defined port you want (you said it works for port checking so...) im not sure if ts the port configuration in the server properties.
where the server IP flag is, try this
server-ip= LOCAL IP/FeedbackLOOP IP/External IP
So assuming you try out your local ip (ex: internal ip address, Ex: 192.168.1.87)
and then try hosting and if it fails try your external ip address, and if those both fail try 127.0.0.1 (feedback loop) address if it works their you go. Otherwise not sure how to resolve it as it sounds more so related to others who try to connect if they cannot connect and you can.
Do what i do for final confirmation if it does or doesn't work.
Login via a different network (just use a wireless hotspot) i use my phone, and other devices to host networks, and then connect (on a seperate isp & Ip) so that if it works i know its not my configurations but someone elses. If it doesn't then i know its on my end.
End point... What the initial fella posted 2 posts before me is the correct explanation.