diff --git a/Net/include/Poco/Net/HTTPClientSession.h b/Net/include/Poco/Net/HTTPClientSession.h
index 14ae999bb9..5cad1bcb46 100644
--- a/Net/include/Poco/Net/HTTPClientSession.h
+++ b/Net/include/Poco/Net/HTTPClientSession.h
@@ -20,9 +20,11 @@
 
 #include "Poco/Net/Net.h"
 #include "Poco/Net/HTTPSession.h"
+#include "Poco/Net/HTTPSessionFactory.h"
 #include "Poco/Net/HTTPBasicCredentials.h"
 #include "Poco/Net/HTTPDigestCredentials.h"
 #include "Poco/Net/HTTPNTLMCredentials.h"
+#include "Poco/Net/ProxyConfig.h"
 #include "Poco/Net/SocketAddress.h"
 #include "Poco/SharedPtr.h"
 #include <istream>
@@ -32,7 +34,6 @@
 namespace Poco {
 namespace Net {
 
-
 class HTTPRequest;
 class HTTPResponse;
 
@@ -65,40 +66,6 @@ class Net_API HTTPClientSession: public HTTPSession
 	/// set up a session through a proxy.
 {
 public:
-	enum ProxyAuthentication
-	{
-		PROXY_AUTH_NONE,        /// No proxy authentication
-		PROXY_AUTH_HTTP_BASIC,  /// HTTP Basic proxy authentication (default, if username and password are supplied)
-		PROXY_AUTH_HTTP_DIGEST, /// HTTP Digest proxy authentication
-		PROXY_AUTH_NTLM         /// NTLMv2 proxy authentication
-	};
-
-	struct ProxyConfig
-		/// HTTP proxy server configuration.
-	{
-		ProxyConfig():
-			port(HTTP_PORT),
-			authMethod(PROXY_AUTH_HTTP_BASIC)
-		{
-		}
-
-		std::string  host;
-			/// Proxy server host name or IP address.
-		Poco::UInt16 port;
-			/// Proxy server TCP port.
-		std::string  username;
-			/// Proxy server username.
-		std::string  password;
-			/// Proxy server password.
-		std::string  nonProxyHosts;
-			/// A regular expression defining hosts for which the proxy should be bypassed,
-			/// e.g. "localhost|127\.0\.0\.1|192\.168\.0\.\d+". Can also be an empty
-			/// string to disable proxy bypassing.
-
-		ProxyAuthentication authMethod;
-			/// The authentication method to use - HTTP Basic or NTLM.
-	};
-
 	HTTPClientSession();
 		/// Creates an unconnected HTTPClientSession.
 
@@ -167,8 +134,8 @@ class Net_API HTTPClientSession: public HTTPSession
 	const SocketAddress& getSourceAddress6();
 		/// Returns the last IPV6 source address set with setSourceAddress
 
-	void setProxy(const std::string& host, Poco::UInt16 port = HTTPSession::HTTP_PORT);
-		/// Sets the proxy host name and port number.
+	void setProxy(const std::string& host, Poco::UInt16 port = HTTPSession::HTTP_PORT, const std::string& protocol = "http", bool tunnel = true);
+		/// Sets the proxy host name, port number, protocol (http or https) and tunnel behaviour.
 
 	void setProxyHost(const std::string& host);
 		/// Sets the host name of the proxy server.
@@ -176,12 +143,24 @@ class Net_API HTTPClientSession: public HTTPSession
 	void setProxyPort(Poco::UInt16 port);
 		/// Sets the port number of the proxy server.
 
+	void setProxyProtocol(const std::string& protocol);
+	        /// Sets the proxy protocol (http or https).
+
+	void setProxyTunnel(bool tunnel);
+		/// If 'true' proxy will be used as tunnel.
+
 	const std::string& getProxyHost() const;
 		/// Returns the proxy host name.
 
 	Poco::UInt16 getProxyPort() const;
 		/// Returns the proxy port number.
 
+	const std::string& getProxyProtocol() const;
+	        /// Returns the proxy protocol.
+
+	bool isProxyTunnel() const;
+		/// Returns 'true' if proxy is configured as tunnel.
+
 	void setProxyCredentials(const std::string& username, const std::string& password);
 		/// Sets the username and password for proxy authentication.
 		/// Only Basic authentication is supported.
@@ -363,6 +342,8 @@ class Net_API HTTPClientSession: public HTTPSession
 		/// Calls proxyConnect() and attaches the resulting StreamSocket
 		/// to the HTTPClientSession.
 
+        HTTPSessionFactory _proxySessionFactory;
+                /// Factory to create HTTPClientSession to proxy.
 private:
 	using OStreamPtr = Poco::SharedPtr<std::ostream>;
 	using IStreamPtr = Poco::SharedPtr<std::istream>;
@@ -422,6 +403,18 @@ inline Poco::UInt16 HTTPClientSession::getProxyPort() const
 }
 
 
+inline const std::string& HTTPClientSession::getProxyProtocol() const
+{
+        return _proxyConfig.protocol;
+}
+
+
+inline bool HTTPClientSession::isProxyTunnel() const
+{
+        return _proxyConfig.tunnel;
+}
+
+
 inline const std::string& HTTPClientSession::getProxyUsername() const
 {
 	return _proxyConfig.username;
@@ -434,13 +427,13 @@ inline const std::string& HTTPClientSession::getProxyPassword() const
 }
 
 
-inline const HTTPClientSession::ProxyConfig& HTTPClientSession::getProxyConfig() const
+inline const ProxyConfig& HTTPClientSession::getProxyConfig() const
 {
 	return _proxyConfig;
 }
 
 
-inline const HTTPClientSession::ProxyConfig& HTTPClientSession::getGlobalProxyConfig()
+inline const ProxyConfig& HTTPClientSession::getGlobalProxyConfig()
 {
 	return _globalProxyConfig;
 }
diff --git a/Net/include/Poco/Net/HTTPSessionFactory.h b/Net/include/Poco/Net/HTTPSessionFactory.h
index 58bbc7a3ff..28fc2e4828 100644
--- a/Net/include/Poco/Net/HTTPSessionFactory.h
+++ b/Net/include/Poco/Net/HTTPSessionFactory.h
@@ -19,7 +19,7 @@
 
 
 #include "Poco/Net/Net.h"
-#include "Poco/Net/HTTPClientSession.h"
+#include "Poco/Net/ProxyConfig.h"
 #include "Poco/Mutex.h"
 #include "Poco/URI.h"
 #include "Poco/SingletonHolder.h"
@@ -30,7 +30,7 @@
 namespace Poco {
 namespace Net {
 
-
+class HTTPClientSession;
 class HTTPSessionInstantiator;
 
 
@@ -52,7 +52,7 @@ class Net_API HTTPSessionFactory
 	HTTPSessionFactory(const std::string& proxyHost, Poco::UInt16 proxyPort);
 		/// Creates the HTTPSessionFactory and sets the proxy host and port.
 
-	HTTPSessionFactory(const HTTPClientSession::ProxyConfig& proxyConfig);
+	HTTPSessionFactory(const ProxyConfig& proxyConfig);
 		/// Creates the HTTPSessionFactory and sets the proxy configuration.
 
 	~HTTPSessionFactory();
@@ -97,10 +97,10 @@ class Net_API HTTPSessionFactory
 	const std::string& proxyPassword() const;
 		/// Returns the password for proxy authorization.
 
-	void setProxyConfig(const HTTPClientSession::ProxyConfig& proxyConfig);
+	void setProxyConfig(const ProxyConfig& proxyConfig);
 		/// Sets the proxy configuration.
 
-	const HTTPClientSession::ProxyConfig& getProxyConfig() const;
+	const ProxyConfig& getProxyConfig() const;
 		/// Returns the proxy configuration.
 
 	static HTTPSessionFactory& defaultFactory();
@@ -122,7 +122,7 @@ class Net_API HTTPSessionFactory
 	typedef std::map<std::string, InstantiatorInfo> Instantiators;
 
 	Instantiators _instantiators;
-	HTTPClientSession::ProxyConfig _proxyConfig;
+	ProxyConfig _proxyConfig;
 
 	mutable Poco::FastMutex _mutex;
 };
@@ -155,7 +155,7 @@ inline const std::string& HTTPSessionFactory::proxyPassword() const
 }
 
 
-inline const HTTPClientSession::ProxyConfig& HTTPSessionFactory::getProxyConfig() const
+inline const ProxyConfig& HTTPSessionFactory::getProxyConfig() const
 {
 	return _proxyConfig;
 }
diff --git a/Net/include/Poco/Net/HTTPSessionInstantiator.h b/Net/include/Poco/Net/HTTPSessionInstantiator.h
index 3cfedfa91c..45b35081cd 100644
--- a/Net/include/Poco/Net/HTTPSessionInstantiator.h
+++ b/Net/include/Poco/Net/HTTPSessionInstantiator.h
@@ -52,14 +52,14 @@ class Net_API HTTPSessionInstantiator
 		/// Unregisters the factory with the global HTTPSessionFactory.
 
 protected:
-	void setProxyConfig(const HTTPClientSession::ProxyConfig& proxyConfig);
+	void setProxyConfig(const ProxyConfig& proxyConfig);
 		/// Sets the proxy configuration.
 
-	const HTTPClientSession::ProxyConfig& getProxyConfig() const;
+	const ProxyConfig& getProxyConfig() const;
 		/// Returns the proxy configuration.
 
 private:
-	HTTPClientSession::ProxyConfig _proxyConfig;
+	ProxyConfig _proxyConfig;
 
 	friend class HTTPSessionFactory;
 };
@@ -68,7 +68,7 @@ class Net_API HTTPSessionInstantiator
 //
 // inlines
 //
-inline const HTTPClientSession::ProxyConfig& HTTPSessionInstantiator::getProxyConfig() const
+inline const ProxyConfig& HTTPSessionInstantiator::getProxyConfig() const
 {
 	return _proxyConfig;
 }
diff --git a/Net/include/Poco/Net/ProxyConfig.h b/Net/include/Poco/Net/ProxyConfig.h
new file mode 100644
index 0000000000..b9d5f05dac
--- /dev/null
+++ b/Net/include/Poco/Net/ProxyConfig.h
@@ -0,0 +1,65 @@
+//
+// ProxyConfig.h
+//
+// Library: Net
+// Package: HTTP
+// Module:  ProxyConfig
+//
+// Definition of the ProxyConfig class.
+//
+// Copyright (c) 2005-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+#ifndef Net_ProxyConfig_INCLUDED
+#define Net_ProxyConfig_INCLUDED
+
+#include "Poco/Net/Net.h"
+#include "Poco/Net/HTTPSession.h"
+
+namespace Poco {
+namespace Net {
+        enum ProxyAuthentication {
+            PROXY_AUTH_NONE,        /// No proxy authentication
+            PROXY_AUTH_HTTP_BASIC,  /// HTTP Basic proxy authentication (default, if username and password are supplied)
+            PROXY_AUTH_HTTP_DIGEST, /// HTTP Digest proxy authentication
+            PROXY_AUTH_NTLM         /// NTLMv2 proxy authentication
+        };
+
+        struct ProxyConfig
+            /// HTTP proxy server configuration.
+        {
+            ProxyConfig() :
+                    port(HTTPSession::HTTP_PORT),
+                    protocol("http"),
+                    tunnel(true),
+                    authMethod(PROXY_AUTH_HTTP_BASIC) {
+            }
+
+            std::string host;
+                /// Proxy server host name or IP address.
+            Poco::UInt16 port;
+                /// Proxy server TCP port.
+            std::string protocol;
+                /// Protocol to use (http or https).
+            bool tunnel;
+            	/// Use proxy as tunnel (establish 2-way communication through CONNECT request).
+                /// If tunnel option is 'false' request will be send directly to proxy without CONNECT request.
+            std::string username;
+                /// Proxy server username.
+            std::string password;
+                /// Proxy server password.
+            std::string nonProxyHosts;
+                /// A regular expression defining hosts for which the proxy should be bypassed,
+                /// e.g. "localhost|127\.0\.0\.1|192\.168\.0\.\d+". Can also be an empty
+                /// string to disable proxy bypassing.
+
+            ProxyAuthentication authMethod;
+                /// The authentication method to use - HTTP Basic or NTLM.
+        };
+
+} } // namespace Poco::Net
+
+#endif // Net_ProxyConfig_INCLUDED
diff --git a/Net/src/HTTPClientSession.cpp b/Net/src/HTTPClientSession.cpp
index 7197e26adb..0b17a8a7e9 100644
--- a/Net/src/HTTPClientSession.cpp
+++ b/Net/src/HTTPClientSession.cpp
@@ -13,6 +13,8 @@
 
 
 #include "Poco/Net/HTTPClientSession.h"
+#include "Poco/Net/HTTPSessionFactory.h"
+#include "Poco/Net/HTTPSessionInstantiator.h"
 #include "Poco/Net/HTTPRequest.h"
 #include "Poco/Net/HTTPResponse.h"
 #include "Poco/Net/HTTPHeaderStream.h"
@@ -35,7 +37,7 @@ namespace Poco {
 namespace Net {
 
 
-HTTPClientSession::ProxyConfig HTTPClientSession::_globalProxyConfig;
+ProxyConfig HTTPClientSession::_globalProxyConfig;
 
 
 HTTPClientSession::HTTPClientSession():
@@ -50,6 +52,7 @@ HTTPClientSession::HTTPClientSession():
 	_responseReceived(false),
 	_ntlmProxyAuthenticated(false)
 {
+        _proxySessionFactory.registerProtocol("http", new HTTPSessionInstantiator);
 }
 
 
@@ -66,6 +69,7 @@ HTTPClientSession::HTTPClientSession(const StreamSocket& socket):
 	_responseReceived(false),
 	_ntlmProxyAuthenticated(false)
 {
+        _proxySessionFactory.registerProtocol("http", new HTTPSessionInstantiator);
 }
 
 
@@ -82,6 +86,7 @@ HTTPClientSession::HTTPClientSession(const SocketAddress& address):
 	_responseReceived(false),
 	_ntlmProxyAuthenticated(false)
 {
+        _proxySessionFactory.registerProtocol("http", new HTTPSessionInstantiator);
 }
 
 
@@ -98,6 +103,7 @@ HTTPClientSession::HTTPClientSession(const std::string& host, Poco::UInt16 port)
 	_responseReceived(false),
 	_ntlmProxyAuthenticated(false)
 {
+        _proxySessionFactory.registerProtocol("http", new HTTPSessionInstantiator);
 }
 
 
@@ -127,11 +133,13 @@ HTTPClientSession::HTTPClientSession(const StreamSocket& socket, const ProxyConf
 	_expectResponseBody(false),
 	_responseReceived(false)
 {
+        _proxySessionFactory.registerProtocol("http", new HTTPSessionInstantiator);
 }
 
 
 HTTPClientSession::~HTTPClientSession()
 {
+        _proxySessionFactory.unregisterProtocol("http");
 }
 
 
@@ -186,14 +194,19 @@ const SocketAddress& HTTPClientSession::getSourceAddress6()
 }
 
 
-void HTTPClientSession::setProxy(const std::string& host, Poco::UInt16 port)
+void HTTPClientSession::setProxy(const std::string& host, Poco::UInt16 port, const std::string& protocol, bool tunnel)
 {
-	if (!connected())
+        if (protocol != "http" && protocol != "https")
+                throw IllegalStateException("Protocol must be either http or https");
+
+        if (!connected())
 	{
 		_proxyConfig.host = host;
 		_proxyConfig.port = port;
+		_proxyConfig.protocol = protocol;
+		_proxyConfig.tunnel = tunnel;
 	}
-	else throw IllegalStateException("Cannot set the proxy host and port for an already connected session");
+        else throw IllegalStateException("Cannot set the proxy host, port and protocol for an already connected session");
 }
 
 
@@ -215,6 +228,28 @@ void HTTPClientSession::setProxyPort(Poco::UInt16 port)
 }
 
 
+void HTTPClientSession::setProxyProtocol(const std::string& protocol)
+{
+        if (protocol != "http" && protocol != "https")
+                throw IllegalStateException("Protocol must be either http or https");
+
+        if (!connected())
+                _proxyConfig.protocol = protocol;
+        else
+                throw IllegalStateException("Cannot set the proxy port number for an already connected session");
+}
+
+
+void HTTPClientSession::setProxyTunnel(bool tunnel)
+{
+        if (!connected())
+                _proxyConfig.tunnel = tunnel;
+        else
+                throw IllegalStateException("Cannot set the proxy tunnel for an already connected session");
+
+}
+
+
 void HTTPClientSession::setProxyCredentials(const std::string& username, const std::string& password)
 {
 	_proxyConfig.username = username;
@@ -476,8 +511,13 @@ std::string HTTPClientSession::proxyRequestPrefix() const
 {
 	std::string result("http://");
 	result.append(_host);
-	result.append(":");
-	NumberFormatter::append(result, _port);
+	/// Do not append default by default, since this may break some servers.
+	/// One example of such server is GCS (Google Cloud Storage).
+	if (_port != HTTPSession::HTTP_PORT)
+	{
+		result.append(":");
+		NumberFormatter::append(result, _port);
+	}
 	return result;
 }
 
@@ -583,25 +623,30 @@ void HTTPClientSession::sendChallengeRequest(const HTTPRequest& request, HTTPRes
 
 StreamSocket HTTPClientSession::proxyConnect()
 {
-	ProxyConfig emptyProxyConfig;
-	HTTPClientSession proxySession(getProxyHost(), getProxyPort(), emptyProxyConfig);
-	proxySession.setTimeout(getTimeout());
+	URI proxyUri;
+        proxyUri.setScheme(getProxyProtocol());
+        proxyUri.setHost(getProxyHost());
+        proxyUri.setPort(getProxyPort());
+
+	SharedPtr<HTTPClientSession> proxySession (_proxySessionFactory.createClientSession(proxyUri));
+
+	proxySession->setTimeout(getTimeout());
 	std::string targetAddress(_host);
 	targetAddress.append(":");
 	NumberFormatter::append(targetAddress, _port);
 	HTTPRequest proxyRequest(HTTPRequest::HTTP_CONNECT, targetAddress, HTTPMessage::HTTP_1_1);
 	HTTPResponse proxyResponse;
 	proxyRequest.set(HTTPMessage::PROXY_CONNECTION, HTTPMessage::CONNECTION_KEEP_ALIVE);
-	proxyRequest.set(HTTPRequest::HOST, getHost());
-	proxySession.proxyAuthenticateImpl(proxyRequest, _proxyConfig);
-	proxySession.setKeepAlive(true);
-	proxySession.setSourceAddress(_sourceAddress4);
-	proxySession.setSourceAddress(_sourceAddress6);
-	proxySession.sendRequest(proxyRequest);
-	proxySession.receiveResponse(proxyResponse);
+	proxyRequest.set(HTTPRequest::HOST, targetAddress);
+	proxySession->proxyAuthenticateImpl(proxyRequest, _proxyConfig);
+	proxySession->setKeepAlive(true);
+	proxySession->setSourceAddress(_sourceAddress4);
+	proxySession->setSourceAddress(_sourceAddress6);
+	proxySession->sendRequest(proxyRequest);
+	proxySession->receiveResponse(proxyResponse);
 	if (proxyResponse.getStatus() != HTTPResponse::HTTP_OK)
 		throw HTTPException("Cannot establish proxy connection", proxyResponse.getReason());
-	return proxySession.detachSocket();
+	return proxySession->detachSocket();
 }
 
 
@@ -621,5 +666,4 @@ bool HTTPClientSession::bypassProxy() const
 	else return false;
 }
 
-
 } } // namespace Poco::Net
diff --git a/Net/src/HTTPSessionFactory.cpp b/Net/src/HTTPSessionFactory.cpp
index 01b86666b2..352e34f554 100644
--- a/Net/src/HTTPSessionFactory.cpp
+++ b/Net/src/HTTPSessionFactory.cpp
@@ -39,7 +39,7 @@ HTTPSessionFactory::HTTPSessionFactory(const std::string& proxyHost, Poco::UInt1
 }
 
 
-HTTPSessionFactory::HTTPSessionFactory(const HTTPClientSession::ProxyConfig& proxyConfig):
+HTTPSessionFactory::HTTPSessionFactory(const ProxyConfig& proxyConfig):
 	_proxyConfig(proxyConfig)
 {
 }
@@ -129,7 +129,7 @@ void HTTPSessionFactory::setProxyCredentials(const std::string& username, const
 }
 
 
-void HTTPSessionFactory::setProxyConfig(const HTTPClientSession::ProxyConfig& proxyConfig)
+void HTTPSessionFactory::setProxyConfig(const ProxyConfig& proxyConfig)
 {
 	FastMutex::ScopedLock lock(_mutex);
 
diff --git a/Net/src/HTTPSessionInstantiator.cpp b/Net/src/HTTPSessionInstantiator.cpp
index e92d8a4de5..71a31a79d0 100644
--- a/Net/src/HTTPSessionInstantiator.cpp
+++ b/Net/src/HTTPSessionInstantiator.cpp
@@ -58,7 +58,7 @@ void HTTPSessionInstantiator::unregisterInstantiator()
 }
 
 
-void HTTPSessionInstantiator::setProxyConfig(const HTTPClientSession::ProxyConfig& proxyConfig)
+void HTTPSessionInstantiator::setProxyConfig(const ProxyConfig& proxyConfig)
 {
 	_proxyConfig = proxyConfig;
 }
diff --git a/Net/testsuite/src/HTTPClientSessionTest.cpp b/Net/testsuite/src/HTTPClientSessionTest.cpp
index b7bf375e4d..ab5279153c 100644
--- a/Net/testsuite/src/HTTPClientSessionTest.cpp
+++ b/Net/testsuite/src/HTTPClientSessionTest.cpp
@@ -22,6 +22,7 @@
 
 
 using Poco::Net::HTTPClientSession;
+using Poco::Net::ProxyConfig;
 using Poco::Net::HTTPRequest;
 using Poco::Net::HTTPResponse;
 using Poco::Net::HTTPMessage;
@@ -298,7 +299,7 @@ void HTTPClientSessionTest::testProxyAuth()
 
 void HTTPClientSessionTest::testBypassProxy()
 {
-	HTTPClientSession::ProxyConfig proxyConfig;
+	ProxyConfig proxyConfig;
 	proxyConfig.host = "proxy.domain.com";
 	proxyConfig.port = 80;
 	proxyConfig.nonProxyHosts = "localhost|127\\.0\\.0\\.1";
diff --git a/NetSSL_OpenSSL/src/HTTPSClientSession.cpp b/NetSSL_OpenSSL/src/HTTPSClientSession.cpp
index 73cc3f61dd..a48b620a9e 100644
--- a/NetSSL_OpenSSL/src/HTTPSClientSession.cpp
+++ b/NetSSL_OpenSSL/src/HTTPSClientSession.cpp
@@ -13,6 +13,7 @@
 
 
 #include "Poco/Net/HTTPSClientSession.h"
+#include "Poco/Net/HTTPSSessionInstantiator.h"
 #include "Poco/Net/SecureStreamSocket.h"
 #include "Poco/Net/SecureStreamSocketImpl.h"
 #include "Poco/Net/SSLManager.h"
@@ -36,6 +37,7 @@ HTTPSClientSession::HTTPSClientSession():
 	_pContext(SSLManager::instance().defaultClientContext())
 {
 	setPort(HTTPS_PORT);
+	_proxySessionFactory.registerProtocol("https", new HTTPSSessionInstantiator);
 }
 
 
@@ -44,6 +46,7 @@ HTTPSClientSession::HTTPSClientSession(const SecureStreamSocket& socket):
 	_pContext(socket.context())
 {
 	setPort(HTTPS_PORT);
+        _proxySessionFactory.registerProtocol("https", new HTTPSSessionInstantiator);
 }
 
 
@@ -53,6 +56,7 @@ HTTPSClientSession::HTTPSClientSession(const SecureStreamSocket& socket, Session
 	_pSession(pSession)
 {
 	setPort(HTTPS_PORT);
+        _proxySessionFactory.registerProtocol("https", new HTTPSSessionInstantiator);
 }
 
 
@@ -62,6 +66,7 @@ HTTPSClientSession::HTTPSClientSession(const std::string& host, Poco::UInt16 por
 {
 	setHost(host);
 	setPort(port);
+        _proxySessionFactory.registerProtocol("https", new HTTPSSessionInstantiator);
 }
 
 
@@ -69,6 +74,7 @@ HTTPSClientSession::HTTPSClientSession(Context::Ptr pContext):
 	HTTPClientSession(SecureStreamSocket(pContext)),
 	_pContext(pContext)
 {
+        _proxySessionFactory.registerProtocol("https", new HTTPSSessionInstantiator(pContext));
 }
 
 
@@ -77,6 +83,7 @@ HTTPSClientSession::HTTPSClientSession(Context::Ptr pContext, Session::Ptr pSess
 	_pContext(pContext),
 	_pSession(pSession)
 {
+        _proxySessionFactory.registerProtocol("https", new HTTPSSessionInstantiator(pContext));
 }
 
 
@@ -86,6 +93,7 @@ HTTPSClientSession::HTTPSClientSession(const std::string& host, Poco::UInt16 por
 {
 	setHost(host);
 	setPort(port);
+        _proxySessionFactory.registerProtocol("https", new HTTPSSessionInstantiator(pContext));
 }
 
 
@@ -96,11 +104,13 @@ HTTPSClientSession::HTTPSClientSession(const std::string& host, Poco::UInt16 por
 {
 	setHost(host);
 	setPort(port);
+        _proxySessionFactory.registerProtocol("https", new HTTPSSessionInstantiator(pContext));
 }
 
 
 HTTPSClientSession::~HTTPSClientSession()
 {
+        _proxySessionFactory.unregisterProtocol("https");
 }
 
 
@@ -126,7 +136,15 @@ X509Certificate HTTPSClientSession::serverCertificate()
 
 std::string HTTPSClientSession::proxyRequestPrefix() const
 {
-	return std::string();
+        std::string result("https://");
+        result.append(getHost());
+        /// Do not append default by default, since this may break some servers.
+        /// One example of such server is GCS (Google Cloud Storage).
+        if (getPort() != HTTPS_PORT) {
+                result.append(":");
+                NumberFormatter::append(result, getPort());
+        }
+        return result;
 }
 
 
@@ -137,33 +155,35 @@ void HTTPSClientSession::proxyAuthenticate(HTTPRequest& request)
 
 void HTTPSClientSession::connect(const SocketAddress& address)
 {
-	if (getProxyHost().empty() || bypassProxy())
-	{
-		SecureStreamSocket sss(socket());
-		if (sss.getPeerHostName().empty())
-		{
-			sss.setPeerHostName(getHost());
-		}
-		if (_pContext->sessionCacheEnabled())
-		{
-			sss.useSession(_pSession);
-		}
-		HTTPSession::connect(address);
-		if (_pContext->sessionCacheEnabled())
-		{
-			_pSession = sss.currentSession();
-		}
-	}
-	else
-	{
-		StreamSocket proxySocket(proxyConnect());
-		SecureStreamSocket secureSocket = SecureStreamSocket::attach(proxySocket, getHost(), _pContext, _pSession);
-		attachSocket(secureSocket);
-		if (_pContext->sessionCacheEnabled())
-		{
-			_pSession = secureSocket.currentSession();
-		}
-	}
+        bool useProxy = !getProxyHost().empty() && !bypassProxy();
+
+        if (useProxy && isProxyTunnel())
+        {
+                StreamSocket proxySocket(proxyConnect());
+                SecureStreamSocket secureSocket = SecureStreamSocket::attach(proxySocket, getHost(), _pContext, _pSession);
+                attachSocket(secureSocket);
+                if (_pContext->sessionCacheEnabled())
+                {
+                        _pSession = secureSocket.currentSession();
+                }
+        }
+        else
+        {
+                SecureStreamSocket sss(socket());
+                if (sss.getPeerHostName().empty())
+                {
+                        sss.setPeerHostName(useProxy ? getProxyHost() : getHost());
+                }
+                if (_pContext->sessionCacheEnabled())
+                {
+                        sss.useSession(_pSession);
+                }
+                HTTPSession::connect(address);
+                if (_pContext->sessionCacheEnabled())
+                {
+                        _pSession = sss.currentSession();
+                }
+    }
 }