Server requirements can be found over in the docs:

http://laravel.com/docs/installation#server-requirements

Does it require Composor and other stuffs besides the server requirement mentioned in that above link ?

Like, I have got an Ubuntu server edition with LAMP and MCrypt installed. I can't simply copy/paste the development folder (laravel app folder) . right? I might need other packages know ??

That's reason I have seen many Laravel dev are opting for Fortrabbit. But in my intranet case, what should I do?

You can download the composer.phar file and run this in the terminal. After composer.phar install you can remove that file. This wont change your server setup at all! You can also just copy the whole application. If it is running on your dev system and you copy ALL files it shouldnt break.

Doesn't it require us to run "artisan serve" command to start the serve every time ?

Sivaganeshsg,

Artisan serve should only be used for development. You should use a full HTTP server like Apache or nginx for production serving - even for an intranet application.

Thank you :)