diff --git a/src/java/davmail/DavGateway.java b/src/java/davmail/DavGateway.java
index 8f21a846..7e871952 100644
--- a/src/java/davmail/DavGateway.java
+++ b/src/java/davmail/DavGateway.java
@@ -7,6 +7,7 @@ import davmail.ldap.LdapServer;
 import davmail.pop.PopServer;
 import davmail.smtp.SmtpServer;
 import davmail.tray.DavGatewayTray;
+import davmail.exchange.ExchangeSessionFactory;
 import org.apache.commons.httpclient.HttpClient;
 import org.apache.commons.httpclient.HttpStatus;
 import org.apache.commons.httpclient.methods.GetMethod;
@@ -33,6 +34,8 @@ public class DavGateway {
      * @param args command line parameter config file path
      */
     public static void main(String[] args) {
+        // enable system proxy setup
+        System.setProperty("java.net.useSystemProxies","true");
 
         if (args.length >= 1) {
             Settings.setConfigFilePath(args[0]);
@@ -45,10 +48,9 @@ public class DavGateway {
     }
 
     public static void start() {
-        // first stop existing servers
-        DavGateway.stop();
-
         try {
+            // prepare HTTP connection pool
+            DavGatewayHttpClientFacade.start();
             smtpServer = new SmtpServer(Settings.getIntProperty("davmail.smtpPort"));
             popServer = new PopServer(Settings.getIntProperty("davmail.popPort"));
             caldavServer = new CaldavServer(Settings.getIntProperty("davmail.caldavPort"));
@@ -94,6 +96,10 @@ public class DavGateway {
         stopServer(popServer);
         stopServer(caldavServer);
         stopServer(ldapServer);
+        // close pooled connections
+        DavGatewayHttpClientFacade.stop();
+        // clear session cache
+        ExchangeSessionFactory.reset();
     }
 
     public static String getCurrentVersion() {
diff --git a/src/java/davmail/exchange/ExchangeSessionFactory.java b/src/java/davmail/exchange/ExchangeSessionFactory.java
index 7011b8b1..69016dfe 100644
--- a/src/java/davmail/exchange/ExchangeSessionFactory.java
+++ b/src/java/davmail/exchange/ExchangeSessionFactory.java
@@ -69,7 +69,7 @@ public class ExchangeSessionFactory {
 
         public void clean() {
             while (!isEmpty()) {
-                pop().close();
+                pop();
             }
         }
     }
@@ -101,7 +101,6 @@ public class ExchangeSessionFactory {
 
             if (session != null && session.isExpired()) {
                 ExchangeSession.LOGGER.debug("Session " + session + " expired");
-                session.close();
                 session = null;
             }
 
@@ -134,8 +133,7 @@ public class ExchangeSessionFactory {
                     sessionStack = new ExchangeSessionStack();
                     poolMap.put(poolKey, sessionStack);
                 }
-                // keep httpClient, but close HTTP connection
-                session.close();
+                // keep httpClient
                 sessionStack.push(session);
                 ExchangeSession.LOGGER.debug("Pooled session: " + session);
             }
@@ -218,4 +216,8 @@ public class ExchangeSessionFactory {
         }
         return up;
     }
+
+    public static void reset() {
+        poolMap.clear();
+    }
 }
diff --git a/src/java/davmail/http/DavGatewayHttpClientFacade.java b/src/java/davmail/http/DavGatewayHttpClientFacade.java
index e11b72ea..276fa87a 100644
--- a/src/java/davmail/http/DavGatewayHttpClientFacade.java
+++ b/src/java/davmail/http/DavGatewayHttpClientFacade.java
@@ -6,15 +6,18 @@ import org.apache.commons.httpclient.*;
 import org.apache.commons.httpclient.methods.GetMethod;
 
 import java.io.IOException;
+import java.net.*;
+import java.net.URI;
+import java.util.List;
 
 /**
  * Create HttpClient instance according to DavGateway Settings
  */
 public class DavGatewayHttpClientFacade {
-    static final MultiThreadedHttpConnectionManager multiThreadedHttpConnectionManager = new MultiThreadedHttpConnectionManager();
+    static MultiThreadedHttpConnectionManager multiThreadedHttpConnectionManager;
 
     static {
-        multiThreadedHttpConnectionManager.setMaxConnectionsPerHost(10);
+        DavGatewayHttpClientFacade.start();
         // force XML response with Internet Explorer header
         System.getProperties().setProperty("httpclient.useragent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)");
     }
@@ -46,12 +49,39 @@ public class DavGatewayHttpClientFacade {
         httpClient.getState().setAuthenticationPreemptive(false);
 
         boolean enableProxy = Settings.getBooleanProperty("davmail.enableProxy");
+        boolean systemProxy = Settings.getBooleanProperty("davmail.systemProxy");
         String proxyHost = null;
         int proxyPort = 0;
         String proxyUser = null;
         String proxyPassword = null;
 
-        if (enableProxy) {
+        if (systemProxy) {
+            String url = Settings.getProperty("davmail.url");
+            try {
+                List<Proxy> proxyList = ProxySelector.getDefault().select(
+                        new URI(url));
+                // get first returned proxy
+                if (proxyList.size() > 0) {
+                    Proxy proxy = proxyList.get(0);
+                    if (proxy.equals(Proxy.NO_PROXY)) {
+                        DavGatewayTray.debug("System proxy : direct connection");
+                    } else {
+                        InetSocketAddress addr = (InetSocketAddress) proxy.address();
+                        proxyHost = addr.getHostName();
+                        proxyPort = addr.getPort();
+                        // no way to get credentials from system proxy
+                        proxyUser = Settings.getProperty("davmail.proxyUser");
+                        proxyPassword = Settings.getProperty("davmail.proxyPassword");
+
+                        DavGatewayTray.debug("System proxy : " + proxyHost + ":" + proxyPort);
+                    }
+
+                }
+            } catch (URISyntaxException e) {
+                DavGatewayTray.error(e);
+            }
+
+        } else if (enableProxy) {
             proxyHost = Settings.getProperty("davmail.proxyHost");
             proxyPort = Settings.getIntProperty("davmail.proxyPort");
             proxyUser = Settings.getProperty("davmail.proxyUser");
@@ -154,4 +184,18 @@ public class DavGatewayHttpClientFacade {
         // caller will need to release connection
         return method;
     }
+
+    public static void stop() {
+        if (multiThreadedHttpConnectionManager != null) {
+            multiThreadedHttpConnectionManager.shutdown();
+            multiThreadedHttpConnectionManager = null;
+        }
+    }
+
+    public static void start() {
+        if (multiThreadedHttpConnectionManager == null) {
+            multiThreadedHttpConnectionManager = new MultiThreadedHttpConnectionManager();
+            multiThreadedHttpConnectionManager.setMaxConnectionsPerHost(10);
+        }
+    }
 }
diff --git a/src/java/davmail/ui/SettingsFrame.java b/src/java/davmail/ui/SettingsFrame.java
index ea556b07..f24b133e 100644
--- a/src/java/davmail/ui/SettingsFrame.java
+++ b/src/java/davmail/ui/SettingsFrame.java
@@ -282,6 +282,7 @@ public class SettingsFrame extends JFrame {
                 dispose();
                 Settings.save();
                 // restart listeners with new config
+                DavGateway.stop();
                 DavGateway.start();
             }
         };