diff --git a/README.md b/README.md
index 7101038..5fdd3d2 100644
--- a/README.md
+++ b/README.md
@@ -104,6 +104,15 @@ Windows default: *false*
 
 *false* is the only effective option on Windows due to platform and library limitations within the supported versions.
 
+### Proxies
+
+A HTTP proxy can be set if your environment can't connect out through PHP or the `curl` binrary natively:
+
+```php
+$client = new \Raygun4php\RaygunClient("apiKey");
+$client->setProxy('http://someproxy:8080');
+```
+
 ### Debug mode
 
 The client offers a debug mode in which the HTTP response code can be returned after a POST attempt. This can be useful when adding Raygun to your site. This is accessed by passing in *true* as the third parameter in the client constructor:
@@ -203,6 +212,7 @@ If, when running a PHP script from the command line on *nix operating systems, y
 
 ## Changelog
 
+- 1.6.0: Added HTTP proxy support, support X-Forwarded-For, null server var guards
 - 1.5.3: Unify property casing (internal change)
 - 1.5.2: Prevent error when query_string isn't present in $_SERVER
 - 1.5.1: Guard against intermittent user id cookie being null; overload for disabling user tracking
diff --git a/src/Raygun4php/RaygunClient.php b/src/Raygun4php/RaygunClient.php
index 2ae42c6..1d3a4ac 100755
--- a/src/Raygun4php/RaygunClient.php
+++ b/src/Raygun4php/RaygunClient.php
@@ -22,6 +22,7 @@ class RaygunClient
     protected $useAsyncSending;
     protected $debugSending;
     protected $disableUserTracking;
+    protected $proxy;
 
     /**
      * @var Array Parameter names to filter out of logged form data. Case insensitive.
@@ -296,12 +297,23 @@ private function post($data_to_send, $cert_path)
         $result = stream_context_set_option($context, 'ssl', 'allow_self_signed', true);
       }
 
+      if ($this->proxy) {
+        $result = stream_context_set_option($context, 'http', 'proxy', $this->proxy);
+      }
+
       if ($this->useAsyncSending && strtoupper(substr(PHP_OS, 0, 3)) !== 'WIN')
       {
-        $cmd = "curl -X POST -H 'Content-Type: application/json' -H 'X-ApiKey: " . $this->apiKey . "'";
-        $cmd .= " -d " . escapeshellarg($data_to_send) . " --cacert '" . realpath(__DIR__ . '/cacert.crt')
-           . "' 'https://api.raygun.io:443/entries' > /dev/null 2>&1 &";
-
+        $curlOpts = array(
+          "-X POST",
+          "-H 'Content-Type: application/json'",
+          "-H 'X-ApiKey: " . $this->apiKey . "'",
+          "-d " . escapeshellarg($data_to_send),
+          "--cacert '" . realpath(__DIR__ . '/cacert.crt') . "'"
+        );
+        if ($this->proxy) {
+          $curlOpts[] = "--proxy '" . $this->proxy . "'";
+        }
+        $cmd = "curl " . implode(' ', $curlOpts) . " 'https://api.raygun.io:443/entries' > /dev/null 2>&1 &";
         exec($cmd, $output, $exit);
         return $exit;
       }
@@ -432,6 +444,24 @@ function getFilterParams() {
       return $this->filterParams;
     }
 
+    /**
+     * Use a proxy for sending HTTP requests to Raygun.
+     * 
+     * @param String $url URL including protocol and an optional port, e.g. http://myproxy:8080
+     * @return Raygun4php\RaygunClient
+     */
+    function setProxy($proxy) {
+      $this->proxy = $proxy;
+      return $this;
+    }
+
+    /**
+     * @return String
+     */
+    function getProxy() {
+      return $this->proxy;
+    }
+
     public function __destruct()
     {
       if ($this->httpData)
diff --git a/src/Raygun4php/RaygunClientMessage.php b/src/Raygun4php/RaygunClientMessage.php
index 977e2e6..9b63e38 100644
--- a/src/Raygun4php/RaygunClientMessage.php
+++ b/src/Raygun4php/RaygunClientMessage.php
@@ -10,7 +10,7 @@ class RaygunClientMessage
         public function __construct()
         {
             $this->Name = "Raygun4php";
-            $this->Version = "1.5.3";
+            $this->Version = "1.6.0";
             $this->ClientUrl = "https://github.com/MindscapeHQ/raygun4php";
         }
     }
diff --git a/src/Raygun4php/RaygunRequestMessage.php b/src/Raygun4php/RaygunRequestMessage.php
index 7f3e61c..c2c30f7 100644
--- a/src/Raygun4php/RaygunRequestMessage.php
+++ b/src/Raygun4php/RaygunRequestMessage.php
@@ -16,10 +16,10 @@ class RaygunRequestMessage
         public function __construct()
         {
             if (php_sapi_name() !== 'cli') {
-                $this->HostName = $_SERVER['HTTP_HOST'];
-                $this->HttpMethod = $_SERVER['REQUEST_METHOD'];
-                $this->Url = $_SERVER['REQUEST_URI'];
-                $this->IpAddress = $_SERVER['REMOTE_ADDR'];
+                $this->HostName = (isset($_SERVER['HTTP_HOST'])) ? $_SERVER['HTTP_HOST'] : null;
+                $this->HttpMethod = (isset($_SERVER['REQUEST_METHOD'])) ? $_SERVER['REQUEST_METHOD'] : null;
+                $this->Url = (isset($_SERVER['REQUEST_URI'])) ? $_SERVER['REQUEST_URI'] :  null;
+                $this->IpAddress = $this->getRemoteAddr();
 
                 if (array_key_exists('QUERY_STRING', $_SERVER))
                 {
@@ -99,5 +99,21 @@ private function emu_getAllHeaders()
                 return getallheaders();
             }
         }
+
+        private function getRemoteAddr()
+        {
+            $ip = null;
+
+            if (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))
+            {
+              $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
+            }
+            else if (!empty($_SERVER['REMOTE_ADDR']))
+            {
+              $ip = $_SERVER['REMOTE_ADDR'];
+            }
+
+            return $ip;
+        }
     }
 }
\ No newline at end of file