diff --git a/README.md b/README.md
index 99c9018..b92ca25 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,29 @@ Almost, but not really. Environment checks differ from unit tests in two importa
  * **They test environment specific settings.** Unit tests are designed to use dummy data and mock interfaces to external system.  Environment checks check the real systems and data that the given environment is actually connected to.
  * **They can't modify data.** Because these checks will run using production databases, they can't go modifying the data in there. This is the biggest reason why we haven't used the same base class as a unit test for writing environment checks - we wanted to make it impossible to accidentally plug a unit test into the environment checker!
 
+## Installation
+
+Register checks in your own `_config.php` - see the `_config.php` in this module for some defaults.
+
+	:::php
+	EnvironmentCheckSuite::register('health', 'DatabaseCheck', "Can we connect to the database?");
+	EnvironmentCheckSuite::register('check', 'URLCheck("")', "Is the homepage accessible?");
+
+## Available checks
+
+ * `DatabaseCheck`: Check that the connection to the database is working, by looking for records in some table. By default, Member will be checked.
+ * `URLCheck`: Check that a given URL is functioning, by default, the homepage.
+ * `HasFunctionCheck`: Check that the given function exists.
+    This can be used to check that PHP modules or features are installed.
+ * `HasClassCheck`: Check that the given class exists.
+    This can be used to check that PHP modules or features are installed.
+ * `FileWriteableCheck`: Check that the given file is writeable.
+ * `FileAgeCheck`: Checks for the maximum age of one or more files or folders.
+    Useful for files which should be frequently auto-generated, 
+    like static caches, as well as for backup files and folders.
+ * `ExternalURLCheck`: Checks that one or more URLs are reachable via HTTP.
+ * `SMTPConnectCheck`: Checks if the SMTP connection configured through PHP.ini works as expected.
+
 ## Adding more checks
 
 To add more checks, you should put additional `EnvironmentCheckSuite::register` calls into your `_config.php`.  See the `_config.php` file of this module for examples.
diff --git a/_config.php b/_config.php
index 4956798..e2dab15 100644
--- a/_config.php
+++ b/_config.php
@@ -1,25 +1,25 @@
 <?php
 
-// These power dev/health, which can be used by load balancers and other such systems
-EnvironmentCheckSuite::register('health', 'DatabaseCheck');
+// // These power dev/health, which can be used by load balancers and other such systems
+// EnvironmentCheckSuite::register('health', 'DatabaseCheck');
 
-// These power dev/check, which is used for diagnostics and for deployment
-EnvironmentCheckSuite::register('check', 'DatabaseCheck("Member")', "Is the database accessible?");
-EnvironmentCheckSuite::register('check', 'URLCheck("")', "Is the homepage accessible?");
+// // These power dev/check, which is used for diagnostics and for deployment
+// EnvironmentCheckSuite::register('check', 'DatabaseCheck("Member")', "Is the database accessible?");
+// EnvironmentCheckSuite::register('check', 'URLCheck("")', "Is the homepage accessible?");
 
-EnvironmentCheckSuite::register('check', 'HasFunctionCheck("curl_init")', "Does PHP have CURL support?");
-EnvironmentCheckSuite::register('check', 'HasFunctionCheck("imagecreatetruecolor")', "Does PHP have GD2 support?");
-EnvironmentCheckSuite::register('check', 'HasFunctionCheck("xml_set_object")', "Does PHP have XML support?");
-EnvironmentCheckSuite::register('check', 'HasFunctionCheck("token_get_all")', "Does PHP have tokenizer support?");
-EnvironmentCheckSuite::register('check', 'HasFunctionCheck("iconv")', "Does PHP have iconv support?");
-EnvironmentCheckSuite::register('check', 'HasFunctionCheck("hash")', "Does PHP have hash support?");
-EnvironmentCheckSuite::register('check', 'HasFunctionCheck("session_start")', "Does PHP have session support?");
-EnvironmentCheckSuite::register('check', 'HasClassCheck("DOMDocument")', "Does PHP have DOMDocument support?");
+// EnvironmentCheckSuite::register('check', 'HasFunctionCheck("curl_init")', "Does PHP have CURL support?");
+// EnvironmentCheckSuite::register('check', 'HasFunctionCheck("imagecreatetruecolor")', "Does PHP have GD2 support?");
+// EnvironmentCheckSuite::register('check', 'HasFunctionCheck("xml_set_object")', "Does PHP have XML support?");
+// EnvironmentCheckSuite::register('check', 'HasFunctionCheck("token_get_all")', "Does PHP have tokenizer support?");
+// EnvironmentCheckSuite::register('check', 'HasFunctionCheck("iconv")', "Does PHP have iconv support?");
+// EnvironmentCheckSuite::register('check', 'HasFunctionCheck("hash")', "Does PHP have hash support?");
+// EnvironmentCheckSuite::register('check', 'HasFunctionCheck("session_start")', "Does PHP have session support?");
+// EnvironmentCheckSuite::register('check', 'HasClassCheck("DOMDocument")', "Does PHP have DOMDocument support?");
 
-EnvironmentCheckSuite::register('check', 'FileWriteableCheck("assets")', "Is assets/ writeable?");
-EnvironmentCheckSuite::register('check', 'FileWriteableCheck("' . TEMP_FOLDER . '")', "Is the temp folder writeable?");
+// EnvironmentCheckSuite::register('check', 'FileWriteableCheck("assets")', "Is assets/ writeable?");
+// EnvironmentCheckSuite::register('check', 'FileWriteableCheck("' . TEMP_FOLDER . '")', "Is the temp folder writeable?");
 
 Director::addRules(100, array(
-	'dev/health' => 'DevHealth',
-	'dev/check' => 'DevCheck',
+	'dev/health' => 'DevHealthController',
+	'dev/check' => 'DevCheckController',
 ));
\ No newline at end of file
diff --git a/code/DefaultHealthChecks.php b/code/DefaultHealthChecks.php
deleted file mode 100644
index 500d6bf..0000000
--- a/code/DefaultHealthChecks.php
+++ /dev/null
@@ -1,157 +0,0 @@
-<?php
-
-/**
- * This file contains a number of default environment checks that you can use.
- */
-
-
-/**
- * Check that the connection to the database is working, by looking for records in some table.
- * By default, Member will be checked.
- * 
- * @param $checkTable The table that will be checked.
- */
-class DatabaseCheck implements EnvironmentCheck {
-	protected $checkTable;
-	
-	function __construct($checkTable = "Member") {
-		$this->checkTable = $checkTable;
-	}
-	
-	function check() {
-		$count = DB::query("SELECT COUNT(*) FROM \"$this->checkTable\"")->value();
-		
-		if($count > 0) {
-			return array(EnvironmentCheck::OK, "");
-		} else {
-			return array(EnvironmentCheck::WARNING, "$this->checkTable queried ok but has no records");
-		}
-	}
-}
-
-/**
- * Check that a given URL is functioning, by default, the homepage.
- * 
- * Note that Director::test() will be used rather than a CURL check.
- */
-class URLCheck implements EnvironmentCheck {
-	protected $url;
-	protected $testString;
-	
-	/*
-	 * @param $url The URL to check, relative to the site.  "" is the homepage.
-	 * @param $testString A piece of text to optionally search for in the homepage HTML.  If omitted, no such check is made.
-	 */
-	function __construct($url = "", $testString = "") {
-		$this->url = $url;
-		$this->testString = $testString;
-	}
-	
-	function check() {
-		$response = Director::test($this->url);
-
-		if($response->getStatusCode() != 200) {
-			return array(EnvironmentCheck::ERROR, "Homepage requested and returned HTTP " . $response->getStatusCode() . " response");
-
-		} else if($this->testString && (strpos($response->getBody(), $this->testString) === false)) {
-			return array(EnvironmentCheck::WARNING, "Homepage requested ok but '$testString' not found.");
-
-		} else {
-			return array(EnvironmentCheck::OK, "");
-		}
-	}
-}
-
-/**
- * Check that the given function exists.
- * This can be used to check that PHP modules or features are installed.
- * @param $functionName The name of the function to look for.
- */
-class HasFunctionCheck implements EnvironmentCheck {
-	protected $functionName;
-	
-	function __construct($functionName) {
-		$this->functionName = $functionName;
-	}
-	
-	function check() {
-		if(function_exists($this->functionName)) return array(EnvironmentCheck::OK, $this->functionName.'() exists');
-		else return array(EnvironmentCheck::ERROR, $this->functionName.'() doesn\'t exist');
-	}
-}
-
-/**
- * Check that the given class exists.
- * This can be used to check that PHP modules or features are installed.
- * @param $className The name of the class to look for.
- */
-class HasClassCheck implements EnvironmentCheck {
-	protected $className;
-	
-	function __construct($className) {
-		$this->className = $className;
-	}
-	
-	function check() {
-		if(class_exists($this->className)) return array(EnvironmentCheck::OK, 'Class ' . $this->className.' exists');
-		else return array(EnvironmentCheck::ERROR, 'Class ' . $this->className.' doesn\'t exist');
-	}
-}
-
-/**
- * Check that the given file is writeable.
- * This can be used to check that the environment doesn't have permission set-up errors.
- * @param $path The full path.  If a relative path, it will relative to the BASE_PATH
- */
-class FileWriteableCheck implements EnvironmentCheck {
-	protected $path;
-	
-	function __construct($path) {
-		$this->path = $path;
-	}
-	
-	function check() {
-		if($this->path[0] == '/') $filename = $this->path;
-		else $filename = BASE_PATH . DIRECTORY_SEPARATOR . str_replace('/', DIRECTORY_SEPARATOR, $this->path);
-		
-		if(file_exists($filename)) $isWriteable = is_writeable($filename);
-		else $isWriteable = is_writeable(dirname($filename));
-		
-		if(!$isWriteable) {
-			if(function_exists('posix_getgroups')) {
-				$userID = posix_geteuid();
-				$user = posix_getpwuid($userID);
-
-				$currentOwnerID = fileowner(file_exists($filename) ? $filename : dirname($filename) );
-				$currentOwner = posix_getpwuid($currentOwnerID);
-
-				$message = "User '$user[name]' needs to be able to write to this file:\n$filename\n\nThe file is currently owned by '$currentOwner[name]'.  ";
-
-				if($user['name'] == $currentOwner['name']) {
-					$message .= "We recommend that you make the file writeable.";
-				} else {
-					
-					$groups = posix_getgroups();
-					$groupList = array();
-					foreach($groups as $group) {
-						$groupInfo = posix_getgrgid($group);
-						if(in_array($currentOwner['name'], $groupInfo['members'])) $groupList[] = $groupInfo['name'];
-					}
-					if($groupList) {
-						$message .= "	We recommend that you make the file group-writeable and change the group to one of these groups:\n - ". implode("\n - ", $groupList)
-							. "\n\nFor example:\nchmod g+w $filename\nchgrp " . $groupList[0] . " $filename";  		
-					} else {
-						$message .= "  There is no user-group that contains both the web-server user and the owner of this file.  Change the ownership of the file, create a new group, or temporarily make the file writeable by everyone during the install process.";
-					}
-				}
-
-			} else {
-				$message .= "The webserver user needs to be able to write to this file:\n$filename";
-			}
-			
-			return array(EnvironmentCheck::ERROR, $message);
-		}
-
-		return array(EnvironmentCheck::OK,'');
-	}
-}
\ No newline at end of file
diff --git a/code/DevCheck.php b/code/DevCheckController.php
similarity index 79%
rename from code/DevCheck.php
rename to code/DevCheckController.php
index 8df6086..6c9884b 100644
--- a/code/DevCheck.php
+++ b/code/DevCheckController.php
@@ -1,6 +1,6 @@
 <?php
 
-class DevCheck extends Controller {
+class DevCheckController extends Controller {
 	function index() {
 		if(!Permission::check("ADMIN")) return Security::permissionFailure();
 		
diff --git a/code/DevHealth.php b/code/DevHealthController.php
similarity index 72%
rename from code/DevHealth.php
rename to code/DevHealthController.php
index df816d2..273d107 100644
--- a/code/DevHealth.php
+++ b/code/DevHealthController.php
@@ -1,6 +1,6 @@
 <?php
 
-class DevHealth extends Controller {
+class DevHealthController extends Controller {
 	function index() {
 		$e = new EnvironmentChecker('health', 'Site health');
 		$e->setErrorCode(404);
diff --git a/code/EnvironmentCheck.php b/code/EnvironmentCheck.php
index 12d785e..0b3af58 100644
--- a/code/EnvironmentCheck.php
+++ b/code/EnvironmentCheck.php
@@ -27,149 +27,4 @@ interface EnvironmentCheck {
 	 */
 	function check();
 
-}
-
-/**
- * Represents a suite of environment checks.
- * Also has a register for assigning environment checks to named instances of EnvironmentCheckSuite
- * 
- * Usage:
- * EnvironmentCheckSuite::register('health', 'MyHealthCheck');
- * 
- * $result = EnvironmentCheckSuite::inst('health')->run();
- */
-class EnvironmentCheckSuite {
-	protected $checks = array();
-	
-	/**
-	 * Run this test suite
-	 * @return The result code of the worst result.
-	 */
-	public function run() {
-		$worstResult = 0;
-		
-		$result = new EnvironmentCheckSuiteResult;
-		foreach($this->checkInstances() as $check) {
-			list($checkClass, $checkTitle) = $check;
-			try {
-				list($status, $message) = $checkClass->check();
-			// If the check fails, register that as an error
-			} catch(Exception $e) {
-				$status = EnvironmentCheck::ERROR;
-				$message = $e->getMessage();
-			}
-			$result->addResult($status, $message, $checkTitle);
-		}
-		
-		return $result;
-	}
-	
-	/**
-	 * Get instances of all the environment checks
-	 */
-	protected function checkInstances() {
-		$output = array();
-		foreach($this->checks as $check) {
-			list($checkClass, $checkTitle) = $check;
-			if(is_string($checkClass)) {
-				$checkInst = Object::create_from_string($checkClass);
-				if($checkInst instanceof EnvironmentCheck) {
-					$output[] = array($checkInst, $checkTitle);
-				} else {
-					throw new InvalidArgumentException("Bad EnvironmentCheck: '$checkClass' - the named class doesn't implement EnvironmentCheck");
-				}
-			} else if($checkClass instanceof EnvironmentCheck) {
-				$output[] = array($checkClass, $checkTitle);
-			} else {
-				throw new InvalidArgumentException("Bad EnvironmentCheck: " . var_export($check, true));
-			}
-		}
-		return $output;
-	}
-	
-	/**
-	 * Add a check to this suite.
-	 * 
-	 */
-	public function push($check, $title = null) {
-		if(!$title) {
-			$title = is_string($check) ? $check : get_class($check);
-		}
-		$this->checks[] = array($check, $title);
-	}
-	
-	/////////////////////////////////////////////////////////////////////////////////////////////
-	
-	protected static $instances = array();
-	
-	/**
-	 * Return a named instance of EnvironmentCheckSuite.
-	 */
-	static function inst($name) {
-		if(!isset(self::$instances[$name])) self::$instances[$name] = new EnvironmentCheckSuite();
-		return self::$instances[$name];
-	}
-
-	/**
-	 * Register a check against the named check suite
-	 */
-	static function register($name, $check, $title = null) {
-		self::inst($name)->push($check, $title);
-	}
-}
-
-/**
- * A single set of results from running an EnvironmentCheckSuite
- */
-class EnvironmentCheckSuiteResult extends ViewableData {
-	protected $details, $worst = 0;
-	
-	function __construct() {
-		parent::__construct();
-		$this->details = new DataObjectSet();
-	}
-	
-	function addResult($status, $message, $checkIdentifier) {
-		$this->details->push(new ArrayData(array(
-			'Check' => $checkIdentifier,
-			'Status' => $this->statusText($status),
-			'Message' => $message,
-		)));
-		
-		$this->worst = max($this->worst, $status);
-	}
-	
-	/**
-	 * Returns true if there are no ERRORs, only WARNINGs or OK
-	 */
-	function ShouldPass() {
-		return $this->worst <= EnvironmentCheck::WARNING;
-	}
-	
-	/**
-	 * Returns overall (i.e. worst) status as a string.
-	 */
-	function Status() {
-		return $this->statusText($this->worst);
-	}
-	
-	/**
-	 * Returns detailed status information about each check
-	 */
-	function Details() {
-		return $this->details;
-	}
-		
-	/**
-	 * Return a text version of a status code
-	 */
-	protected function statusText($status) {
-		switch($status) {
-			case EnvironmentCheck::ERROR: return "ERROR";
-			case EnvironmentCheck::WARNING: return "WARNING";
-			case EnvironmentCheck::OK: return "OK";
-			case 0: return "NO CHECKS";
-			default: throw new InvalidArgumentException("Bad environment check status '$status'");
-		}
-	}
 }
\ No newline at end of file
diff --git a/code/EnvironmentCheckSuite.php b/code/EnvironmentCheckSuite.php
new file mode 100644
index 0000000..6041d3f
--- /dev/null
+++ b/code/EnvironmentCheckSuite.php
@@ -0,0 +1,148 @@
+<?php
+/**
+ * Represents a suite of environment checks.
+ * Also has a register for assigning environment checks to named instances of EnvironmentCheckSuite
+ * 
+ * Usage:
+ * EnvironmentCheckSuite::register('health', 'MyHealthCheck');
+ * 
+ * $result = EnvironmentCheckSuite::inst('health')->run();
+ */
+class EnvironmentCheckSuite {
+	protected $checks = array();
+	
+	/**
+	 * Run this test suite
+	 * @return The result code of the worst result.
+	 */
+	public function run() {
+		$worstResult = 0;
+		
+		$result = new EnvironmentCheckSuiteResult;
+		foreach($this->checkInstances() as $check) {
+			list($checkClass, $checkTitle) = $check;
+			try {
+				list($status, $message) = $checkClass->check();
+			// If the check fails, register that as an error
+			} catch(Exception $e) {
+				$status = EnvironmentCheck::ERROR;
+				$message = $e->getMessage();
+			}
+			$result->addResult($status, $message, $checkTitle);
+		}
+		
+		return $result;
+	}
+	
+	/**
+	 * Get instances of all the environment checks
+	 */
+	protected function checkInstances() {
+		$output = array();
+		foreach($this->checks as $check) {
+			list($checkClass, $checkTitle) = $check;
+			if(is_string($checkClass)) {
+				$checkInst = Object::create_from_string($checkClass);
+				if($checkInst instanceof EnvironmentCheck) {
+					$output[] = array($checkInst, $checkTitle);
+				} else {
+					throw new InvalidArgumentException("Bad EnvironmentCheck: '$checkClass' - the named class doesn't implement EnvironmentCheck");
+				}
+			} else if($checkClass instanceof EnvironmentCheck) {
+				$output[] = array($checkClass, $checkTitle);
+			} else {
+				throw new InvalidArgumentException("Bad EnvironmentCheck: " . var_export($check, true));
+			}
+		}
+		return $output;
+	}
+	
+	/**
+	 * Add a check to this suite.
+	 * 
+	 */
+	public function push($check, $title = null) {
+		if(!$title) {
+			$title = is_string($check) ? $check : get_class($check);
+		}
+		$this->checks[] = array($check, $title);
+	}
+	
+	/////////////////////////////////////////////////////////////////////////////////////////////
+	
+	protected static $instances = array();
+	
+	/**
+	 * Return a named instance of EnvironmentCheckSuite.
+	 */
+	static function inst($name) {
+		if(!isset(self::$instances[$name])) self::$instances[$name] = new EnvironmentCheckSuite();
+		return self::$instances[$name];
+	}
+
+	/**
+	 * Register a check against the named check suite.
+	 * 
+	 * @param String|Array
+	 */
+	static function register($names, $check, $title = null) {
+		if(!is_array($names)) $names = array($names);
+		foreach($names as $name) self::inst($name)->push($check, $title);
+	}
+}
+
+/**
+ * A single set of results from running an EnvironmentCheckSuite
+ */
+class EnvironmentCheckSuiteResult extends ViewableData {
+	protected $details, $worst = 0;
+	
+	function __construct() {
+		parent::__construct();
+		$this->details = new DataObjectSet();
+	}
+	
+	function addResult($status, $message, $checkIdentifier) {
+		$this->details->push(new ArrayData(array(
+			'Check' => $checkIdentifier,
+			'Status' => $this->statusText($status),
+			'Message' => $message,
+		)));
+		
+		$this->worst = max($this->worst, $status);
+	}
+	
+	/**
+	 * Returns true if there are no ERRORs, only WARNINGs or OK
+	 */
+	function ShouldPass() {
+		return $this->worst <= EnvironmentCheck::WARNING;
+	}
+	
+	/**
+	 * Returns overall (i.e. worst) status as a string.
+	 */
+	function Status() {
+		return $this->statusText($this->worst);
+	}
+	
+	/**
+	 * Returns detailed status information about each check
+	 */
+	function Details() {
+		return $this->details;
+	}
+		
+	/**
+	 * Return a text version of a status code
+	 */
+	protected function statusText($status) {
+		switch($status) {
+			case EnvironmentCheck::ERROR: return "ERROR";
+			case EnvironmentCheck::WARNING: return "WARNING";
+			case EnvironmentCheck::OK: return "OK";
+			case 0: return "NO CHECKS";
+			default: throw new InvalidArgumentException("Bad environment check status '$status'");
+		}
+	}
+}
\ No newline at end of file
diff --git a/code/checks/DatabaseCheck.php b/code/checks/DatabaseCheck.php
new file mode 100644
index 0000000..9696c0f
--- /dev/null
+++ b/code/checks/DatabaseCheck.php
@@ -0,0 +1,29 @@
+<?php
+/**
+ * This file contains a number of default environment checks that you can use.
+ */
+
+
+/**
+ * Check that the connection to the database is working, by looking for records in some table.
+ * By default, Member will be checked.
+ * 
+ * @param $checkTable The table that will be checked.
+ */
+class DatabaseCheck implements EnvironmentCheck {
+	protected $checkTable;
+	
+	function __construct($checkTable = "Member") {
+		$this->checkTable = $checkTable;
+	}
+	
+	function check() {
+		$count = DB::query("SELECT COUNT(*) FROM \"$this->checkTable\"")->value();
+		
+		if($count > 0) {
+			return array(EnvironmentCheck::OK, "");
+		} else {
+			return array(EnvironmentCheck::WARNING, "$this->checkTable queried ok but has no records");
+		}
+	}
+}
\ No newline at end of file
diff --git a/code/checks/ExternalURLCheck.php b/code/checks/ExternalURLCheck.php
new file mode 100644
index 0000000..a8a09b5
--- /dev/null
+++ b/code/checks/ExternalURLCheck.php
@@ -0,0 +1,110 @@
+<?php
+/**
+ * Checks that one or more URLs are reachable via HTTP.
+ * Note that the HTTP connectivity can just be verified from the server to the remote URL,
+ * it can still fail if the URL in question is requested by the client, e.g. through an iframe.
+ * 
+ * Requires curl to present, so ensure to check it before with the following:
+ * <code>EnvironmentCheckSuite::register('check', 'HasFunctionCheck("curl_init")', "Does PHP have CURL support?");</code>
+ */
+class ExternalURLCheck implements EnvironmentCheck {
+
+	/**
+	 * @var array
+	 */
+	protected $urls = array();
+
+	/**
+	 * @var Int Timeout in seconds.
+	 */
+	protected $timeout;
+
+	/**
+	 * @param String Space separated list of absolute URLs 
+	 *  (can't be an array as we're using Object::create() with strings for the constructor signature)
+	 */
+	function __construct($urls, $timeout = 15) {
+		if($urls) $this->urls = explode(' ', $urls);
+		$this->timeout = $timeout;
+	}
+
+	function check() {
+		$urls = $this->getURLs();
+
+		$chs = array();
+		foreach($urls as $url)	{
+			$ch = curl_init();
+			$chs[] = $ch;
+			curl_setopt_array($ch, $this->getCurlOpts($url));
+		}	
+		// Parallel execution for faster performance
+		$mh = curl_multi_init();
+		foreach($chs as $ch) curl_multi_add_handle($mh,$ch);
+		
+		$active = null;
+		// Execute the handles
+		do {
+			$mrc = curl_multi_exec($mh, $active);
+		} while ($mrc == CURLM_CALL_MULTI_PERFORM);
+
+		while ($active && $mrc == CURLM_OK) {
+			if (curl_multi_select($mh) != -1) {
+				do {
+						$mrc = curl_multi_exec($mh, $active);
+				} while ($mrc == CURLM_CALL_MULTI_PERFORM);
+			}
+		}
+
+		$hasError = false;
+		$msgs = array();
+		foreach($chs as $ch) {
+			$url = curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);
+			$code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
+			if(curl_errno($ch) || $code >= 400) {
+				$hasError = true;
+				$msgs[] = sprintf(
+					'Error retrieving "%s": %s (Code: %s)',
+					$url,
+					curl_error($ch),
+					$code
+				);
+			} else {
+				$msgs[] = sprintf(
+					'Success retrieving "%s" (Code: %s)',
+					$url,
+					$code
+				);
+			}
+		}
+
+		// Close the handles
+		foreach($chs as $ch) curl_multi_remove_handle($mh, $ch);
+		curl_multi_close($mh);
+		
+		if($hasError) {
+			return array(EnvironmentCheck::ERROR, implode(', ', $msgs));
+		} else {
+			return array(EnvironmentCheck::OK, implode(', ', $msgs));
+		}
+	}
+
+	/**
+	 * @return Array
+	 */
+	protected function getCurlOpts($url) {
+		return array(
+			CURLOPT_URL => $url,
+			CURLOPT_HEADER => 0,
+			CURLOPT_RETURNTRANSFER => 1,
+			CURLOPT_FAILONERROR => 1,
+			CURLOPT_TIMEOUT => $this->timeout,
+		);
+	}
+
+	/**
+	 * @return Array
+	 */
+	protected function getURLs() {
+		return $this->urls;
+	}
+}
\ No newline at end of file
diff --git a/code/checks/FileAgeCheck.php b/code/checks/FileAgeCheck.php
new file mode 100644
index 0000000..b531983
--- /dev/null
+++ b/code/checks/FileAgeCheck.php
@@ -0,0 +1,106 @@
+<?php
+/**
+ * Checks for the maximum age of one or more files or folders.
+ * Useful for files which should be frequently auto-generated, 
+ * like static caches, as well as for backup files and folders.
+ * Does NOT check for existence of a file (will silently fail).
+ *
+ * Examples:
+ * // Checks that Requirements::combine_files() has regenerated files in the last 24h
+ * EnvironmentCheckSuite::register(
+ * 	'check', 
+ * 	'FileAgeCheck("' . ASSETS_PATH . '/_combined_files/*.js' . '", "-1 day", '>', " . FileAgeCheck::CHECK_ALL) . "'
+ * );
+ * 
+ * // Checks that at least one backup folder has been created in the last 24h
+ * EnvironmentCheckSuite::register(
+ * 	'check', 
+ * 	'FileAgeCheck("' . BASE_PATH . '/../backups/*' . '", "-1 day", '>', " . FileAgeCheck::CHECK_SINGLE) . "'
+ * );
+ */
+class FileAgeCheck implements EnvironmentCheck {
+
+	const CHECK_SINGLE = 1;
+
+	const CHECK_ALL = 2;
+	
+	/**
+	 * @var String Absolute path to a file or folder, compatible with glob().
+	 */
+	protected $path;
+
+	/**
+	 * @var String strtotime() compatible relative date specification.
+	 */
+	protected $relativeAge;
+
+	/**
+	 * @var String The function to use for checking file age,
+	 * so filemtime(), filectime() or fileatime().
+	 */
+	protected $checkFn;
+
+	/**
+	 * @var Int Constant, check for a single file to match age criteria, or all of them.
+	 */
+	protected $checkType;
+
+	/**
+	 * @var String Either '>' or '<'.
+	 */
+	protected $compareOperand;
+
+	function __construct($path, $relativeAge, $compareOperand = '>', $checkType = null, $checkFn = 'filemtime') {
+		$this->path = $path;
+		$this->relativeAge = $relativeAge;
+		$this->checkFn = $checkFn;
+		$this->checkType = ($checkType) ? $checkType : self::CHECK_SINGLE;
+		$this->compareOperand = $compareOperand;
+	}
+
+	function check() {
+		$cutoffTime =  strtotime($this->relativeAge, SS_Datetime::now()->Format('U'));
+		$files = $this->getFiles();
+		$invalidFiles = array();
+		$validFiles = array();
+		$checkFn = $this->checkFn;
+		$allValid = true;
+		if($files) foreach($files as $file) {
+			$fileTime = $checkFn($file);
+			$valid = ($this->compareOperand == '>') ? ($fileTime >= $cutoffTime) : ($fileTime <= $cutoffTime);
+			if($valid) {
+				$validFiles[] = $file;
+			} else {
+				$invalidFiles[] = $file;
+				if($this->checkType == self::CHECK_ALL) {
+					return array(
+						EnvironmentCheck::ERROR,
+						sprintf(
+							'File "%s" doesn\'t match age check (compare %s: %s, actual: %s)', 
+							$file, $this->compareOperand, date('c', $cutoffTime), date('c', $fileTime)
+						)
+					);	
+				}
+			}
+		}
+
+		// If at least one file was valid, count as passed
+		if($this->checkType == self::CHECK_SINGLE && count($invalidFiles) < count($files)) {
+			return array(EnvironmentCheck::OK, '');
+		} else {
+			return array(
+				EnvironmentCheck::ERROR,
+				sprintf('No files matched criteria (%s %s)', $this->compareOperand, date('c', $cutoffTime))
+			);
+		}
+			
+	}
+
+	/**
+	 * @return Array Of absolute file paths
+	 */
+	protected function getFiles() {
+		return glob($this->path);
+	}
+
+}
\ No newline at end of file
diff --git a/code/checks/FileWriteableCheck.php b/code/checks/FileWriteableCheck.php
new file mode 100644
index 0000000..3d3ae98
--- /dev/null
+++ b/code/checks/FileWriteableCheck.php
@@ -0,0 +1,58 @@
+<?php
+/**
+ * Check that the given file is writeable.
+ * This can be used to check that the environment doesn't have permission set-up errors.
+ * @param $path The full path.  If a relative path, it will relative to the BASE_PATH
+ */
+class FileWriteableCheck implements EnvironmentCheck {
+	protected $path;
+	
+	function __construct($path) {
+		$this->path = $path;
+	}
+	
+	function check() {
+		if($this->path[0] == '/') $filename = $this->path;
+		else $filename = BASE_PATH . DIRECTORY_SEPARATOR . str_replace('/', DIRECTORY_SEPARATOR, $this->path);
+		
+		if(file_exists($filename)) $isWriteable = is_writeable($filename);
+		else $isWriteable = is_writeable(dirname($filename));
+		
+		if(!$isWriteable) {
+			if(function_exists('posix_getgroups')) {
+				$userID = posix_geteuid();
+				$user = posix_getpwuid($userID);
+
+				$currentOwnerID = fileowner(file_exists($filename) ? $filename : dirname($filename) );
+				$currentOwner = posix_getpwuid($currentOwnerID);
+
+				$message = "User '$user[name]' needs to be able to write to this file:\n$filename\n\nThe file is currently owned by '$currentOwner[name]'.  ";
+
+				if($user['name'] == $currentOwner['name']) {
+					$message .= "We recommend that you make the file writeable.";
+				} else {
+					
+					$groups = posix_getgroups();
+					$groupList = array();
+					foreach($groups as $group) {
+						$groupInfo = posix_getgrgid($group);
+						if(in_array($currentOwner['name'], $groupInfo['members'])) $groupList[] = $groupInfo['name'];
+					}
+					if($groupList) {
+						$message .= "	We recommend that you make the file group-writeable and change the group to one of these groups:\n - ". implode("\n - ", $groupList)
+							. "\n\nFor example:\nchmod g+w $filename\nchgrp " . $groupList[0] . " $filename";  		
+					} else {
+						$message .= "  There is no user-group that contains both the web-server user and the owner of this file.  Change the ownership of the file, create a new group, or temporarily make the file writeable by everyone during the install process.";
+					}
+				}
+
+			} else {
+				$message .= "The webserver user needs to be able to write to this file:\n$filename";
+			}
+			
+			return array(EnvironmentCheck::ERROR, $message);
+		}
+
+		return array(EnvironmentCheck::OK,'');
+	}
+}
\ No newline at end of file
diff --git a/code/checks/HasClassCheck.php b/code/checks/HasClassCheck.php
new file mode 100644
index 0000000..db372fa
--- /dev/null
+++ b/code/checks/HasClassCheck.php
@@ -0,0 +1,18 @@
+<?php
+/**
+ * Check that the given class exists.
+ * This can be used to check that PHP modules or features are installed.
+ * @param $className The name of the class to look for.
+ */
+class HasClassCheck implements EnvironmentCheck {
+	protected $className;
+	
+	function __construct($className) {
+		$this->className = $className;
+	}
+	
+	function check() {
+		if(class_exists($this->className)) return array(EnvironmentCheck::OK, 'Class ' . $this->className.' exists');
+		else return array(EnvironmentCheck::ERROR, 'Class ' . $this->className.' doesn\'t exist');
+	}
+}
\ No newline at end of file
diff --git a/code/checks/HasFunctionCheck.php b/code/checks/HasFunctionCheck.php
new file mode 100644
index 0000000..2f3d78b
--- /dev/null
+++ b/code/checks/HasFunctionCheck.php
@@ -0,0 +1,18 @@
+<?php
+/**
+ * Check that the given function exists.
+ * This can be used to check that PHP modules or features are installed.
+ * @param $functionName The name of the function to look for.
+ */
+class HasFunctionCheck implements EnvironmentCheck {
+	protected $functionName;
+	
+	function __construct($functionName) {
+		$this->functionName = $functionName;
+	}
+	
+	function check() {
+		if(function_exists($this->functionName)) return array(EnvironmentCheck::OK, $this->functionName.'() exists');
+		else return array(EnvironmentCheck::ERROR, $this->functionName.'() doesn\'t exist');
+	}
+}
\ No newline at end of file
diff --git a/code/checks/SMTPConnectCheck.php b/code/checks/SMTPConnectCheck.php
new file mode 100644
index 0000000..d3dfb8c
--- /dev/null
+++ b/code/checks/SMTPConnectCheck.php
@@ -0,0 +1,58 @@
+<?php
+/**
+ * Checks if the SMTP connection configured through PHP.ini works as expected.
+ * Only checks socket connection with HELO command, not actually sending the email.
+ */
+class SMTPConnectCheck implements EnvironmentCheck {
+
+	/**
+	 * @var String
+	 */
+	protected $host;
+
+	/**
+	 * @var Int
+	 */
+	protected $port;
+
+	/**
+	 * @var Int In seconds
+	 */
+	protected $timeout;
+
+	/**
+	 * @param String
+	 * @param Int
+	 */
+	function __construct($host = null, $port = null, $timeout = 15) {
+		$this->host = ($host) ? $host : ini_get('SMTP');
+		if(!$this->host) $this->host = 'localhost';
+		
+		$this->port = ($port) ? $port : ini_get('smtp_port');
+		if(!$this->port) $this->port = 25;
+
+		$this->timeout = $timeout;
+	}
+
+	function check() {
+		$f = @fsockopen($this->host, $this->port, $errno, $errstr, $this->timeout);
+		if(!$f) {
+			return array(
+				EnvironmentCheck::ERROR, 
+				sprintf("Couldn't connect to SMTP on %s:%s (Error: %s %s)", $this->host, $this->port, $errno, $errstr)
+			);
+		}
+
+		fwrite($f, "HELO its_me\r\n");
+		$response = fread($f, 26);
+		if(substr($response, 0, 3) != '220') {
+			return array(
+				EnvironmentCheck::ERROR,
+				sprintf("Invalid mail server response: %s", $response)
+			);
+		}
+
+		return array(EnvironmentCheck::OK, '');
+
+	}
+}
\ No newline at end of file
diff --git a/code/checks/URLCheck.php b/code/checks/URLCheck.php
new file mode 100644
index 0000000..6db586b
--- /dev/null
+++ b/code/checks/URLCheck.php
@@ -0,0 +1,42 @@
+<?php
+/**
+ * Check that a given URL is functioning, by default, the homepage.
+ * 
+ * Note that Director::test() will be used rather than a CURL check.
+ */
+class URLCheck implements EnvironmentCheck {
+	protected $url;
+	protected $testString;
+	
+	/*
+	 * @param $url The URL to check, relative to the site.  "" is the homepage.
+	 * @param $testString A piece of text to optionally search for in the homepage HTML.  If omitted, no such check is made.
+	 */
+	function __construct($url = "", $testString = "") {
+		$this->url = $url;
+		$this->testString = $testString;
+	}
+	
+	function check() {
+		$response = Director::test($this->url);
+
+		if($response->getStatusCode() != 200) {
+			return array(
+				EnvironmentCheck::ERROR, 
+				sprintf('Error retrieving "%s" (Code: %d)', $this->url, $response->getStatusCode())
+			);
+
+		} else if($this->testString && (strpos($response->getBody(), $this->testString) === false)) {
+			return array(
+				EnvironmentCheck::WARNING, 
+				sprintf('Success retrieving "%s", but string "%s" not found', $this->url, $testString)
+			);
+
+		} else {
+			return array(
+				EnvironmentCheck::OK, 
+				sprintf('Success retrieving "%s"', $this->url)
+			);
+		}
+	}
+}
\ No newline at end of file