diff --git a/code/nel/include/nel/gui/group_html.h b/code/nel/include/nel/gui/group_html.h
index da90095a3..969eac1f7 100644
--- a/code/nel/include/nel/gui/group_html.h
+++ b/code/nel/include/nel/gui/group_html.h
@@ -793,7 +793,7 @@ namespace NLGUI
 		void doBrowseLocalFile(const std::string &filename);
 
 		// load remote content using either GET or POST
-		void doBrowseRemoteUrl(const std::string &url, const std::string &referer, bool doPost = false, const SFormFields &formfields = SFormFields());
+		void doBrowseRemoteUrl(std::string url, const std::string &referer, bool doPost = false, const SFormFields &formfields = SFormFields());
 
 		// render html string as new browser page
 		bool renderHtmlString(const std::string &html);
@@ -861,7 +861,7 @@ namespace NLGUI
 		// BnpDownload system
 		void initBnpDownload();
 		void checkBnpDownload();
-		bool addBnpDownload(const std::string &url, const std::string &action, const std::string &script, const std::string &md5sum);
+		bool addBnpDownload(std::string url, const std::string &action, const std::string &script, const std::string &md5sum);
 		std::string localBnpName(const std::string &url);
 
 		void releaseDownloads();
diff --git a/code/nel/include/nel/gui/http_hsts.h b/code/nel/include/nel/gui/http_hsts.h
new file mode 100644
index 000000000..2693461cd
--- /dev/null
+++ b/code/nel/include/nel/gui/http_hsts.h
@@ -0,0 +1,73 @@
+// Ryzom - MMORPG Framework <http://dev.ryzom.com/projects/ryzom/>
+// Copyright (C) 2010  Winch Gate Property Limited
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef CL_HTTP_HSTS_H
+#define CL_HTTP_HSTS_H
+
+#include "nel/misc/types_nl.h"
+
+namespace NLGUI
+{
+	// ********************************************************************************
+	struct SHSTSObject
+	{
+	public:
+		SHSTSObject(uint64 expires = 0, bool includeSubDomains = false)
+			: Expires(expires)
+			, IncludeSubDomains(includeSubDomains)
+		{ }
+
+		uint64 Expires;
+		bool IncludeSubDomains;
+	};
+
+	/**
+	 * Keeping track of HSTS header
+	 * \author Meelis Mägi (nimetu)
+	 * \date 2017
+	 */
+	class CStrictTransportSecurity
+	{
+	public:
+		typedef std::map<std::string, SHSTSObject> THSTSObject;
+
+		static CStrictTransportSecurity* getInstance();
+		static void release();
+
+	public:
+		bool isSecureHost(const std::string &domain) const;
+
+		// ************************************************************************
+		void init(const std::string& fname);
+		void save();
+
+		void erase(const std::string &domain);
+		void set(const std::string &domain, uint64 expires, bool includeSubDomains);
+		bool get(const std::string &domain, SHSTSObject &hsts) const;
+		void setFromHeader(const std::string &domain, const std::string &header);
+
+		void serial(NLMISC::IStream& f);
+	private:
+		static CStrictTransportSecurity* instance;
+
+		~CStrictTransportSecurity();
+
+		std::string _Filename;
+		THSTSObject _Domains;
+	};
+
+}
+#endif
diff --git a/code/nel/src/gui/group_html.cpp b/code/nel/src/gui/group_html.cpp
index e99149cec..0c082ae58 100644
--- a/code/nel/src/gui/group_html.cpp
+++ b/code/nel/src/gui/group_html.cpp
@@ -46,6 +46,7 @@
 #include "nel/misc/big_file.h"
 #include "nel/gui/url_parser.h"
 #include "nel/gui/http_cache.h"
+#include "nel/gui/http_hsts.h"
 #include "nel/gui/curl_certificates.h"
 
 using namespace std;
@@ -71,6 +72,26 @@ namespace NLGUI
 
 	CGroupHTML::SWebOptions CGroupHTML::options;
 
+	// Return URL with https is host is in HSTS list
+	static std::string upgradeInsecureUrl(const std::string &url)
+	{
+		if (toLower(url.substr(0, 7)) != "http://") {
+			return url;
+		}
+
+		CUrlParser uri(url);
+		if (!CStrictTransportSecurity::getInstance()->isSecureHost(uri.host)){
+			return url;
+		}
+
+	#ifdef LOG_DL
+		nlwarning("HSTS url : '%s', using https", url.c_str());
+	#endif
+		uri.scheme = "https";
+
+		return uri.toString();
+	}
+
 	// Active cURL www transfer
 	class CCurlWWWData
 	{
@@ -149,6 +170,27 @@ namespace NLGUI
 				return "";
 			}
 
+			bool hasHSTSHeader()
+			{
+				// ignore header if not secure connection
+				if (toLower(Url.substr(0, 8)) != "https://")
+				{
+					return false;
+				}
+
+				return HeadersRecv.count("strict-transport-security") > 0;
+			}
+
+			const std::string getHSTSHeader()
+			{
+				if (hasHSTSHeader())
+				{
+					return HeadersRecv["strict-transport-security"];
+				}
+
+				return "";
+			}
+
 		public:
 			CURL *Request;
 
@@ -406,7 +448,7 @@ namespace NLGUI
 	// Add a image download request in the multi_curl
 	void CGroupHTML::addImageDownload(const string &url, CViewBase *img, const CStyleParams &style, TImageType type)
 	{
-		string finalUrl = getAbsoluteUrl(url);
+		string finalUrl = upgradeInsecureUrl(getAbsoluteUrl(url));
 
 		// Search if we are not already downloading this url.
 		for(uint i = 0; i < Curls.size(); i++)
@@ -421,7 +463,7 @@ namespace NLGUI
 			}
 		}
 
-		// use requested url for local name
+		// use requested url for local name (cache)
 		string dest = localImageName(url);
 	#ifdef LOG_DL
 		nlwarning("add to download '%s' dest '%s' img %p", finalUrl.c_str(), dest.c_str(), img);
@@ -467,8 +509,10 @@ namespace NLGUI
 	}
 
 	// Add a bnp download request in the multi_curl, return true if already downloaded
-	bool CGroupHTML::addBnpDownload(const string &url, const string &action, const string &script, const string &md5sum)
+	bool CGroupHTML::addBnpDownload(string url, const string &action, const string &script, const string &md5sum)
 	{
+		url = upgradeInsecureUrl(getAbsoluteUrl(url));
+
 		// Search if we are not already downloading this url.
 		for(uint i = 0; i < Curls.size(); i++)
 		{
@@ -577,6 +621,12 @@ namespace NLGUI
 	#ifdef LOG_DL
 						nlwarning("(%s) web transfer '%p' completed with status %d, http %d, url (len %d) '%s'", _Id.c_str(), _CurlWWW->Request, res, code, _CurlWWW->Url.size(), _CurlWWW->Url.c_str());
 	#endif
+						// save HSTS header from all requests regardless of HTTP code
+						if (res == CURLE_OK && _CurlWWW->hasHSTSHeader())
+						{
+							CUrlParser uri(_CurlWWW->Url);
+							CStrictTransportSecurity::getInstance()->setFromHeader(uri.host, _CurlWWW->getHSTSHeader());
+						}
 
 						if (res != CURLE_OK)
 						{
@@ -663,6 +713,12 @@ namespace NLGUI
 	#endif
 							curl_multi_remove_handle(MultiCurl, it->data->Request);
 
+							// save HSTS header from all requests regardless of HTTP code
+							if (res == CURLE_OK && it->data->hasHSTSHeader())
+							{
+								CStrictTransportSecurity::getInstance()->setFromHeader(uri.host, it->data->getHSTSHeader());
+							}
+
 							string tmpfile = it->dest + ".tmp";
 							if(res != CURLE_OK || r < 200 || r >= 300 || (!it->md5sum.empty() && (it->md5sum != getMD5(tmpfile).toString())))
 							{
@@ -5239,7 +5295,7 @@ namespace NLGUI
 	}
 
 	// ***************************************************************************
-	void CGroupHTML::doBrowseRemoteUrl(const std::string &url, const std::string &referer, bool doPost, const SFormFields &formfields)
+	void CGroupHTML::doBrowseRemoteUrl(std::string url, const std::string &referer, bool doPost, const SFormFields &formfields)
 	{
 		// Stop previous request and remove content
 		stopBrowse ();
@@ -5253,6 +5309,8 @@ namespace NLGUI
 		else
 			setTitle (_TitlePrefix + " - " + CI18N::get("uiPleaseWait"));
 
+		url = upgradeInsecureUrl(url);
+
 	#if LOG_DL
 		nlwarning("(%s) browse url (trusted=%s) '%s', referer='%s', post='%s', nb form values %d",
 				_Id.c_str(), (_TrustedDomain ? "true" :"false"), url.c_str(), referer.c_str(), (doPost ? "true" : "false"), formfields.Values.size());
diff --git a/code/nel/src/gui/http_hsts.cpp b/code/nel/src/gui/http_hsts.cpp
new file mode 100644
index 000000000..980bdabda
--- /dev/null
+++ b/code/nel/src/gui/http_hsts.cpp
@@ -0,0 +1,245 @@
+// Ryzom - MMORPG Framework <http://dev.ryzom.com/projects/ryzom/>
+// Copyright (C) 2010  Winch Gate Property Limited
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include "stdpch.h"
+#include "nel/gui/http_hsts.h"
+
+using namespace std;
+using namespace NLMISC;
+
+#ifdef DEBUG_NEW
+#define new DEBUG_NEW
+#endif
+
+namespace NLGUI {
+	CStrictTransportSecurity* CStrictTransportSecurity::instance = NULL;
+	CStrictTransportSecurity* CStrictTransportSecurity::getInstance()
+	{
+		if (!instance)
+		{
+			instance= new CStrictTransportSecurity();
+		}
+		return instance;
+	}
+
+	void CStrictTransportSecurity::release()
+	{
+		delete instance;
+		instance = NULL;
+	}
+
+	CStrictTransportSecurity::~CStrictTransportSecurity()
+	{
+		save();
+	}
+
+	// ************************************************************************
+	bool CStrictTransportSecurity::isSecureHost(const std::string &domain) const
+	{
+		SHSTSObject hsts;
+		if (get(domain, hsts))
+		{
+			time_t currentTime;
+			time(&currentTime);
+
+			return (hsts.Expires < currentTime);
+		}
+
+		return false;
+	}
+
+	// ************************************************************************
+	void CStrictTransportSecurity::erase(const std::string &domain)
+	{
+		if (_Domains.count(domain) > 0)
+		{
+			_Domains.erase(domain);
+		}
+	}
+
+	void CStrictTransportSecurity::set(const std::string &domain, uint64 expires, bool includeSubDomains)
+	{
+		if (expires == 0)
+		{
+			erase(domain);
+			return;
+		}
+
+		_Domains[domain].Expires = expires;
+		_Domains[domain].IncludeSubDomains = includeSubDomains;
+	}
+
+	bool CStrictTransportSecurity::get(const std::string &domain, SHSTSObject &hsts) const
+	{
+		if (domain.empty() || _Domains.empty())
+			return false;
+
+		if (_Domains.count(domain) > 0)
+		{
+			hsts = _Domains.at(domain);
+			return true;
+		}
+
+		size_t firstOf = domain.find_first_of(".");
+		size_t lastOf = domain.find_last_of(".");
+		while(firstOf != lastOf)
+		{
+			std::string tmp;
+			tmp = domain.substr(firstOf+1);
+			if (_Domains.count(tmp))
+			{
+				if (_Domains.at(tmp).IncludeSubDomains)
+				{
+					hsts = _Domains.at(tmp);
+					return true;
+				}
+
+				return false;
+			}
+
+			firstOf = domain.find_first_of(".",  firstOf + 1);
+		}
+
+		return false;
+	}
+
+	void CStrictTransportSecurity::init(const std::string &fname)
+	{
+		_Domains.clear();
+		_Filename = fname;
+
+		if (_Filename.empty() || !CFile::fileExists(_Filename))
+		{
+			return;
+		}
+
+		CIFile in;
+		if (!in.open(_Filename))
+		{
+			nlwarning("Unable to open %s for reading", _Filename.c_str());
+			return;
+		}
+
+		serial(in);
+	}
+
+	void CStrictTransportSecurity::save()
+	{
+		if (_Filename.empty())
+			return;
+
+		if (_Domains.empty())
+		{
+			CFile::deleteFile(_Filename);
+			return;
+		}
+
+		COFile out;
+		if (!out.open(_Filename))
+		{
+			nlwarning("Unable to open %s for writing", _Filename.c_str());
+			return;
+		}
+
+		serial(out);
+		out.close();
+	}
+
+	void CStrictTransportSecurity::serial(NLMISC::IStream& f)
+	{
+		try
+		{
+			f.serialVersion(1);
+			// HSTS
+			f.serialCheck(NELID("STSH"));
+
+			if (f.isReading())
+			{
+				uint32 nbItems;
+				f.serial(nbItems);
+				for(uint32 k = 0; k < nbItems; ++k)
+				{
+					std::string domain;
+					f.serial(domain);
+					f.serial(_Domains[domain].Expires);
+					f.serial(_Domains[domain].IncludeSubDomains);
+				}
+			}
+			else
+			{
+				uint32 nbItems = _Domains.size();
+				f.serial(nbItems);
+				for (THSTSObject::iterator it = _Domains.begin(); it != _Domains.end(); ++it)
+				{
+					std::string domain(it->first);
+					f.serial(domain);
+					f.serial(_Domains[domain].Expires);
+					f.serial(_Domains[domain].IncludeSubDomains);
+				}
+			}
+		}
+		catch (...)
+		{
+			_Domains.clear();
+			nlwarning("Invalid HTST file format (%s)", _Filename.c_str());
+		}
+	}
+
+	// ***************************************************************************
+	void CStrictTransportSecurity::setFromHeader(const std::string &domain, const std::string &header)
+	{
+		// max-age=<seconds>; includeSubdomains; preload;
+		std::vector<std::string> elements;
+		NLMISC::splitString(toLower(header), ";", elements);
+		if (elements.empty()) return;
+
+		time_t currentTime;
+		time(&currentTime);
+
+		uint64 expire = 0;
+		bool includeSubDomains = false;
+
+		for(uint i=0; i< elements.size(); ++i)
+		{
+			std::string str(trim(elements[i]));
+			if (str.substr(0, 8) == "max-age=")
+			{
+				uint64 ttl;
+				if (fromString(str.substr(8), ttl))
+				{
+					if (ttl > 0)
+					{
+						expire = currentTime + ttl;
+					}
+				}
+			}
+			else if (str == "includesubdomains")
+			{
+				includeSubDomains = true;
+			}
+		}
+
+		if (expire == 0)
+		{
+			erase(domain);
+		}
+		else
+		{
+			set(domain, expire, includeSubDomains);
+		}
+	}
+
+}
diff --git a/code/ryzom/client/src/init.cpp b/code/ryzom/client/src/init.cpp
index 900f3c2c1..244ef3384 100644
--- a/code/ryzom/client/src/init.cpp
+++ b/code/ryzom/client/src/init.cpp
@@ -69,6 +69,7 @@
 #include "interface_v3/sbrick_manager.h"
 #include "nel/gui/widget_manager.h"
 #include "nel/gui/http_cache.h"
+#include "nel/gui/http_hsts.h"
 //
 #include "gabarit.h"
 #include "hair_set.h"
@@ -1370,6 +1371,8 @@ void prelogInit()
 		CHttpCache::getInstance()->setCacheIndex("cache/cache.index");
 		CHttpCache::getInstance()->init();
 
+		CStrictTransportSecurity::getInstance()->init("save/hsts-list.save");
+
 		// Register the reflected classes
 		registerInterfaceElements();
 
diff --git a/code/ryzom/client/src/release.cpp b/code/ryzom/client/src/release.cpp
index a1f3a29c2..ff569b22a 100644
--- a/code/ryzom/client/src/release.cpp
+++ b/code/ryzom/client/src/release.cpp
@@ -95,6 +95,7 @@
 #include "nel/gui/lua_manager.h"
 #include "item_group_manager.h"
 #include "nel/gui/http_cache.h"
+#include "nel/gui/http_hsts.h"
 
 ///////////
 // USING //
@@ -688,6 +689,7 @@ void release()
 	CViewRenderer::release();
 	CIXml::releaseLibXml();
 	CHttpCache::release();
+	CStrictTransportSecurity::release();
 
 #if FINAL_VERSION
 	// openURL ("http://www.ryzomcore.org/exit/");