You really don't need to add anything to the hosts file. The only thing necessary for getting your server online is to make sure your no-ip is set up to point to your current IP properly, and to have that no-ip address in your sql database.
The only thing the hosts file is doing is when your connecting to your server by having "jealy.no-ip.biz" in your realmlist, your computer does a check of the hosts file. Since it finds that line as a "Host" it knows not to look it up on the internet. Basically all your doing is the long version of setting 127.0.0.1 as your realmlist. (That may be different if you are behind a router, but my server doesn't need a "Hosts" file line to work)
So check your firewall... check your router, and check the realm SQL database. The server name can't be MaNGOS and it can't be 127.0.0.1