diff --git a/l10n_update.inc b/l10n_update.inc
index 3567817..d317844 100644
--- a/l10n_update.inc
+++ b/l10n_update.inc
@@ -318,7 +318,8 @@ function l10n_update_http_check($url, $headers = array()) {
  *     received.
  *   - redirect_code: If redirected, an integer containing the initial response
  *     status code.
- *   - redirect_url: If redirected, a string containing the redirection location.
+ *   - redirect_url: If redirected, a string containing the URL of the redirect
+ *     target.
  *   - error: If an error occurred, the error message. Otherwise not set.
  *   - headers: An array containing the response headers as name/value pairs.
  *     HTTP header names are case-insensitive (RFC 2616, section 4.2), so for
@@ -354,10 +355,51 @@ function l10n_update_http_request($url, array $options = array()) {
     'timeout' => 30.0,
     'context' => NULL,
   );
+
+  // Merge the default headers.
+  $options['headers'] += array(
+    'User-Agent' => 'Drupal (+http://drupal.org/)',
+  );
+
   // stream_socket_client() requires timeout to be a float.
   $options['timeout'] = (float) $options['timeout'];
 
+  // Use a proxy if one is defined and the host is not on the excluded list.
+  $proxy_server = variable_get('proxy_server', '');
+  if ($proxy_server && _drupal_http_use_proxy($uri['host'])) {
+    // Set the scheme so we open a socket to the proxy server.
+    $uri['scheme'] = 'proxy';
+    // Set the path to be the full URL.
+    $uri['path'] = $url;
+    // Since the URL is passed as the path, we won't use the parsed query.
+    unset($uri['query']);
+
+    // Add in username and password to Proxy-Authorization header if needed.
+    if ($proxy_username = variable_get('proxy_username', '')) {
+      $proxy_password = variable_get('proxy_password', '');
+      $options['headers']['Proxy-Authorization'] = 'Basic ' . base64_encode($proxy_username . (!empty($proxy_password) ? ":" . $proxy_password : ''));
+    }
+    // Some proxies reject requests with any User-Agent headers, while others
+    // require a specific one.
+    $proxy_user_agent = variable_get('proxy_user_agent', '');
+    // The default value matches neither condition.
+    if ($proxy_user_agent === NULL) {
+      unset($options['headers']['User-Agent']);
+    }
+    elseif ($proxy_user_agent) {
+      $options['headers']['User-Agent'] = $proxy_user_agent;
+    }
+  }
+
   switch ($uri['scheme']) {
+    case 'proxy':
+      // Make the socket connection to a proxy server.
+      $socket = 'tcp://' . $proxy_server . ':' . variable_get('proxy_port', 8080);
+      // The Host header still needs to match the real request.
+      $options['headers']['Host'] = $uri['host'];
+      $options['headers']['Host'] .= isset($uri['port']) && $uri['port'] != 80 ? ':' . $uri['port'] : '';
+      break;
+
     case 'http':
     case 'feed':
       $port = isset($uri['port']) ? $uri['port'] : 80;
@@ -367,12 +409,14 @@ function l10n_update_http_request($url, array $options = array()) {
       // checking the host that do not take into account the port number.
       $options['headers']['Host'] = $uri['host'] . ($port != 80 ? ':' . $port : '');
       break;
+
     case 'https':
       // Note: Only works when PHP is compiled with OpenSSL support.
       $port = isset($uri['port']) ? $uri['port'] : 443;
       $socket = 'ssl://' . $uri['host'] . ':' . $port;
       $options['headers']['Host'] = $uri['host'] . ($port != 443 ? ':' . $port : '');
       break;
+
     default:
       $result->error = 'invalid schema ' . $uri['scheme'];
       $result->code = -1003;
@@ -397,7 +441,7 @@ function l10n_update_http_request($url, array $options = array()) {
     // Mark that this request failed. This will trigger a check of the web
     // server's ability to make outgoing HTTP requests the next time that
     // requirements checking is performed.
-    // See system_requirements()
+    // See system_requirements().
     // variable_set('drupal_http_request_fails', TRUE);
 
     return $result;
@@ -409,11 +453,6 @@ function l10n_update_http_request($url, array $options = array()) {
     $path .= '?' . $uri['query'];
   }
 
-  // Merge the default headers.
-  $options['headers'] += array(
-    'User-Agent' => 'Drupal (+http://drupal.org/)',
-  );
-
   // Only add Content-Length if we actually have any content or if it is a POST
   // or PUT request. Some non-standard servers get confused by Content-Length in
   // at least HEAD/GET requests, and Squid always requires Content-Length in
@@ -425,7 +464,7 @@ function l10n_update_http_request($url, array $options = array()) {
 
   // If the server URL has a user then attempt to use basic authentication.
   if (isset($uri['user'])) {
-    $options['headers']['Authorization'] = 'Basic ' . base64_encode($uri['user'] . (!empty($uri['pass']) ? ":" . $uri['pass'] : ''));
+    $options['headers']['Authorization'] = 'Basic ' . base64_encode($uri['user'] . (isset($uri['pass']) ? ':' . $uri['pass'] : ''));
   }
 
   // If the database prefix is being used by SimpleTest to run the tests in a copied
@@ -480,7 +519,9 @@ function l10n_update_http_request($url, array $options = array()) {
     return $result;
   }
   // Parse response headers from the response body.
-  list($response, $result->data) = explode("\r\n\r\n", $response, 2);
+  // Be tolerant of malformed HTTP responses that separate header and body with
+  // \n\n or \r\r instead of \r\n\r\n.
+  list($response, $result->data) = preg_split("/\r\n\r\n|\n\n|\r\r/", $response, 2);
   $response = preg_split("/\r\n|\n|\r/", $response);
 
   // Parse the response status line.
@@ -572,7 +613,9 @@ function l10n_update_http_request($url, array $options = array()) {
         $result = l10n_update_http_request($location, $options);
         $result->redirect_code = $code;
       }
-      $result->redirect_url = $location;
+      if (!isset($result->redirect_url)) {
+        $result->redirect_url = $location;
+      }
       break;
     default:
       $result->error = $status_message;