Some subdomain stuff for laraval from http://www.reddit.com/r/laravel/comments/1ql5ov/subdomain_routing/cde78sp

filters.php

<?php

App::before(function($request)
{
	// determine the subdomain of the current request
	$server        = explode('.', Request::server('HTTP_HOST'));
	$sansSubdomain = implode('.', array_slice($server, 1));

	// there are 3 parts to the domain (i.e.  user.domain.com)
	if (count($server) == 3)
	{
		// first part of array is the subdomain, duh
		$subdomain = $server[0];

		// check if it's "www" (or similar / mistyped variant)
		if (in_array($subdomain, array('w', 'ww', 'www', 'wwww')))
		{
			// route somewhere or set a config variable 
			// or do nothing because the next condition is where the magic happens
		}
		else if (! is_null($subdomain)) // possibly a meaningful subdomain but we're not sure yet
		{
			// match against your predefined list here
			$predefinedArray = ['a', 'b', 'c', 'd']; // or whatever you need to look up
			$predefinedResults = \ModelName::where('someValue', $subdomain)->first(); // obviously fake

			// if there's a valid matching predefined result
			if (!count($predefinedResults))
			{
				Session::flash('error', $subdomain.' is not a valid subdomain.');
				return Redirect::to('http://'.$sansSubdomain);
			}

			// if this code gets executed, the subdomain is kosher
			// do other data-juggling here if needed

		}
		else // subdomain is invalid or just catch-all depending on your preceding logic
		{
			// present error or handle appropriately for your needs
		}
	}
	else // no apparent subdomain detected
	{
		// do nothing here, will just route normally
		// be careful of creating redirect loops
	}
});