diff --git a/docs/manual.rst b/docs/manual.rst
index b36db463b..42e5e0a5e 100644
--- a/docs/manual.rst
+++ b/docs/manual.rst
@@ -6404,6 +6404,31 @@ I2P errors:
 160    no_i2p_router                             The URL specified an i2p address, but no i2p router is configured
 ====== ========================================= =================================================================
 
+tracker errors:
+
+====== ========================================= =================================================================
+170    scrape_not_available                      The tracker URL doesn't support transforming it into a scrape
+                                                 URL. i.e. it doesn't contain "announce.
+------ ----------------------------------------- -----------------------------------------------------------------
+171    invalid_tracker_response                  invalid tracker response
+------ ----------------------------------------- -----------------------------------------------------------------
+172    invalid_peer_dict                         invalid peer dictionary entry. Not a dictionary
+------ ----------------------------------------- -----------------------------------------------------------------
+173    tracker_failure                           tracker sent a failure message
+------ ----------------------------------------- -----------------------------------------------------------------
+174    invalid_files_entry                       missing or invalid 'files' entry
+------ ----------------------------------------- -----------------------------------------------------------------
+175    invalid_hash_entry                        missing or invalid 'hash' entry
+------ ----------------------------------------- -----------------------------------------------------------------
+176    invalid_peers_entry                       missing or invalid 'peers' and 'peers6' entry
+------ ----------------------------------------- -----------------------------------------------------------------
+177    invalid_tracker_response_length           udp tracker response packet has invalid size
+------ ----------------------------------------- -----------------------------------------------------------------
+178    invalid_tracker_transaction_id            invalid transaction id in udp tracker response
+------ ----------------------------------------- -----------------------------------------------------------------
+179    invalid_tracker_action                    invalid action field in udp tracker response
+====== ========================================= =================================================================
+
 The names of these error codes are declared in then ``libtorrent::errors`` namespace.
 
 There is also another error category, ``libtorrent::upnp_category``, defining errors
diff --git a/include/libtorrent/alert_types.hpp b/include/libtorrent/alert_types.hpp
index 0ff66ddb1..0a23e8fc9 100644
--- a/include/libtorrent/alert_types.hpp
+++ b/include/libtorrent/alert_types.hpp
@@ -241,24 +241,13 @@ namespace libtorrent
 			, int times
 			, int status
 			, std::string const& url_
-			, error_code const& e)
+			, error_code const& e
+			, std::string const& m)
 			: tracker_alert(h, url_)
 			, times_in_row(times)
 			, status_code(status)
-			, msg(e.message())
-		{
-			TORRENT_ASSERT(!url.empty());
-		}
-
-		tracker_error_alert(torrent_handle const& h
-			, int times
-			, int status
-			, std::string const& url_
-			, std::string const& msg_)
-			: tracker_alert(h, url_)
-			, times_in_row(times)
-			, status_code(status)
-			, msg(msg_)
+			, error(e)
+			, msg(msg)
 		{
 			TORRENT_ASSERT(!url.empty());
 		}
@@ -270,6 +259,7 @@ namespace libtorrent
 
 		int times_in_row;
 		int status_code;
+		error_code error;
 		std::string msg;
 	};
 
diff --git a/include/libtorrent/error_code.hpp b/include/libtorrent/error_code.hpp
index 3ca781803..08c45544a 100644
--- a/include/libtorrent/error_code.hpp
+++ b/include/libtorrent/error_code.hpp
@@ -224,6 +224,27 @@ namespace libtorrent
 			reserved159,
 // i2p errors
 			no_i2p_router, // 160
+			reserved161,
+			reserved162,
+			reserved163,
+			reserved164,
+			reserved165,
+			reserved166,
+			reserved167,
+			reserved168,
+			reserved169,
+
+// tracker errors
+			scrape_not_available, // 170
+			invalid_tracker_response,
+			invalid_peer_dict,
+			tracker_failure,
+			invalid_files_entry,
+			invalid_hash_entry,
+			invalid_peers_entry,
+			invalid_tracker_response_length,
+			invalid_tracker_transaction_id,
+			invalid_tracker_action,
 
 			error_code_max
 		};
diff --git a/include/libtorrent/torrent.hpp b/include/libtorrent/torrent.hpp
index d5f36aadd..1f28fd0b9 100644
--- a/include/libtorrent/torrent.hpp
+++ b/include/libtorrent/torrent.hpp
@@ -423,10 +423,9 @@ namespace libtorrent
 			, std::list<address> const& ip_list
 			, std::vector<peer_entry>& e, int interval, int min_interval
 			, int complete, int incomplete, address const& external_ip);
-		virtual void tracker_request_timed_out(
-			tracker_request const& r);
 		virtual void tracker_request_error(tracker_request const& r
-			, int response_code, const std::string& str, int retry_interval);
+			, int response_code, error_code const& ec, const std::string& msg
+			, int retry_interval);
 		virtual void tracker_warning(tracker_request const& req
 			, std::string const& msg);
 		virtual void tracker_scrape_response(tracker_request const& req
diff --git a/include/libtorrent/tracker_manager.hpp b/include/libtorrent/tracker_manager.hpp
index aff77bda6..15f23aede 100644
--- a/include/libtorrent/tracker_manager.hpp
+++ b/include/libtorrent/tracker_manager.hpp
@@ -135,12 +135,11 @@ namespace libtorrent
 			, int complete
 			, int incomplete
 			, address const& external_ip) = 0;
-		virtual void tracker_request_timed_out(
-			tracker_request const& req) = 0;
 		virtual void tracker_request_error(
 			tracker_request const& req
 			, int response_code
-			, const std::string& description
+			, error_code const& ec
+			, const std::string& msg
 			, int retry_interval) = 0;
 
 		union_endpoint m_tracker_address;
@@ -201,9 +200,9 @@ namespace libtorrent
 
 		tracker_request const& tracker_req() const { return m_req; }
 
-		void fail_disp(int code, std::string const& msg) { fail(code, msg.c_str()); }
-		void fail(int code, char const* msg, int interval = 0, int min_interval = 0);
-		void fail_timeout();
+		void fail_disp(error_code ec) { fail(ec); }
+		void fail(error_code const& ec, int code = -1, char const* msg = ""
+			, int interval = 0, int min_interval = 0);
 		virtual void start() = 0;
 		virtual void close();
 		address const& bind_interface() const { return m_req.bind_ip; }
diff --git a/src/error_code.cpp b/src/error_code.cpp
index 00584ffe4..8f67a095c 100644
--- a/src/error_code.cpp
+++ b/src/error_code.cpp
@@ -213,6 +213,26 @@ namespace libtorrent
 			"",
 // i2p errors
 			"no i2p router is set up",
+			"",
+			"",
+			"",
+			"",
+			"",
+			"",
+			"",
+			"",
+			"",
+// tracker errors
+			"scrape not available on tracker",
+			"invalid tracker response",
+			"invalid peer dictionary entry",
+			"tracker sent a failure message",
+			"missing or invalid 'files' entry",
+			"missing or invalid 'hash' entry",
+			"missing or invalid 'peers' and 'peers6' entry",
+			"udp tracker response packet has invalid size",
+			"invalid transaction id in udp tracker response",
+			"invalid action field in udp tracker response",
 		};
 		if (ev < 0 || ev >= sizeof(msgs)/sizeof(msgs[0]))
 			return "Unknown error";
diff --git a/src/http_tracker_connection.cpp b/src/http_tracker_connection.cpp
index c05459c87..a2bec5bed 100644
--- a/src/http_tracker_connection.cpp
+++ b/src/http_tracker_connection.cpp
@@ -108,7 +108,7 @@ namespace libtorrent
 			if (pos == std::string::npos)
 			{
 				m_ios.post(boost::bind(&http_tracker_connection::fail_disp, self()
-					, -1, "scrape is not available on url: '" + tracker_req().url +"'"));
+					, error_code(errors::scrape_not_available)));
 				return;
 			}
 			url.replace(pos, 8, "scrape");
@@ -247,7 +247,7 @@ namespace libtorrent
 		}
 
 		if (endpoints.empty())
-			fail(-1, "blocked by IP filter");
+			fail(error_code(errors::banned_by_ip_filter));
 	}
 
 	void http_tracker_connection::on_connect(http_connection& c)
@@ -267,25 +267,25 @@ namespace libtorrent
 
 		if (ec && ec != asio::error::eof)
 		{
-			fail(-1, ec.message().c_str());
+			fail(ec);
 			return;
 		}
 		
 		if (!parser.header_finished())
 		{
-			fail(-1, "premature end of file");
+			fail(asio::error::eof);
 			return;
 		}
 
 		if (parser.status_code() != 200)
 		{
-			fail(parser.status_code(), parser.message().c_str());
+			fail(error_code(errors::http_error), parser.status_code(), parser.message().c_str());
 			return;
 		}
 	
 		if (ec && ec != asio::error::eof)
 		{
-			fail(parser.status_code(), ec.message().c_str());
+			fail(ec, parser.status_code());
 			return;
 		}
 		
@@ -301,19 +301,7 @@ namespace libtorrent
 		}
 		else
 		{
-			std::string error_str("invalid encoding of tracker response: \"");
-			for (char const* i = data, *end(data + size); i != end; ++i)
-			{
-				if (*i >= ' ' && *i <= '~') error_str += *i;
-				else
-				{
-					char val[30];
-					snprintf(val, sizeof(val), "0x%02x ", *i);
-					error_str += val;
-				}
-			}
-			error_str += "\"";
-			fail(parser.status_code(), error_str.c_str());
+			fail(error_code(errors::invalid_bencoding), parser.status_code());
 		}
 		close();
 	}
@@ -323,7 +311,7 @@ namespace libtorrent
 		// extract peer id (if any)
 		if (info.type() != lazy_entry::dict_t)
 		{
-			fail(-1, "invalid response from tracker (invalid peer entry)");
+			fail(error_code(errors::invalid_peer_dict));
 			return false;
 		}
 		lazy_entry const* i = info.dict_find_string("peer id");
@@ -341,7 +329,7 @@ namespace libtorrent
 		i = info.dict_find_string("ip");
 		if (i == 0)
 		{
-			fail(-1, "invalid response from tracker");
+			fail(error_code(errors::invalid_tracker_response));
 			return false;
 		}
 		ret.ip = i->string_value();
@@ -350,7 +338,7 @@ namespace libtorrent
 		i = info.dict_find_int("port");
 		if (i == 0)
 		{
-			fail(-1, "invalid response from tracker");
+			fail(error_code(errors::invalid_tracker_response));
 			return false;
 		}
 		ret.port = (unsigned short)i->int_value();
@@ -370,7 +358,8 @@ namespace libtorrent
 		lazy_entry const* failure = e.dict_find_string("failure reason");
 		if (failure)
 		{
-			fail(status_code, failure->string_value().c_str(), interval, min_interval);
+			fail(error_code(errors::tracker_failure), status_code
+				, failure->string_value().c_str(), interval, min_interval);
 			return;
 		}
 
@@ -387,7 +376,7 @@ namespace libtorrent
 			lazy_entry const* files = e.dict_find_dict("files");
 			if (files == 0)
 			{
-				fail(-1, "invalid or missing 'files' entry in scrape response"
+				fail(error_code(errors::invalid_files_entry), -1, ""
 					, interval, min_interval);
 				return;
 			}
@@ -395,7 +384,7 @@ namespace libtorrent
 			lazy_entry const* scrape_data = files->dict_find_dict(ih.c_str());
 			if (scrape_data == 0)
 			{
-				fail(-1, "missing or invalid info-hash entry in scrape response"
+				fail(error_code(errors::invalid_hash_entry), -1, ""
 					, interval, min_interval);
 				return;
 			}
@@ -469,7 +458,7 @@ namespace libtorrent
 
 		if (peers_ent == 0 && ipv6_peers == 0)
 		{
-			fail(-1, "missing 'peers' and 'peers6' entry in tracker response"
+			fail(error_code(errors::invalid_peers_entry), -1, ""
 				, interval, min_interval);
 			return;
 		}
diff --git a/src/torrent.cpp b/src/torrent.cpp
index b5d420637..493d37740 100644
--- a/src/torrent.cpp
+++ b/src/torrent.cpp
@@ -6257,49 +6257,11 @@ namespace libtorrent
 		return ret;
 	}
 
-	void torrent::tracker_request_timed_out(
-		tracker_request const& r)
-	{
-		mutex::scoped_lock l(m_ses.m_mutex);
-
-		INVARIANT_CHECK;
-
-#if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
-		debug_log("*** tracker timed out");
-#endif
-
-		if (r.kind == tracker_request::announce_request)
-		{
-			announce_entry* ae = find_tracker(r);
-			if (ae)
-			{
-				ae->failed();
-				int tracker_index = ae - &m_trackers[0];
-				deprioritize_tracker(tracker_index);
-			}
-			if (m_ses.m_alerts.should_post<tracker_error_alert>())
-			{
-				m_ses.m_alerts.post_alert(tracker_error_alert(get_handle()
-					, ae?ae->fails:0, 0, r.url
-					, errors::timed_out));
-			}
-		}
-		else if (r.kind == tracker_request::scrape_request)
-		{
-			if (m_ses.m_alerts.should_post<scrape_failed_alert>())
-			{
-				m_ses.m_alerts.post_alert(scrape_failed_alert(get_handle()
-					, r.url, errors::timed_out));
-			}
-		}
-		update_tracker_timer();
-	}
-
 	// TODO: with some response codes, we should just consider
 	// the tracker as a failure and not retry
 	// it anymore
 	void torrent::tracker_request_error(tracker_request const& r
-		, int response_code, const std::string& str
+		, int response_code, error_code const& ec, const std::string& msg
 		, int retry_interval)
 	{
 		mutex::scoped_lock l(m_ses.m_mutex);
@@ -6307,7 +6269,7 @@ namespace libtorrent
 		INVARIANT_CHECK;
 
 #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
-		debug_log(std::string("*** tracker error: ") + str);
+		debug_log("*** tracker error: " + ec.message() + " " + msg);
 #endif
 		if (r.kind == tracker_request::announce_request)
 		{
@@ -6321,14 +6283,14 @@ namespace libtorrent
 			if (m_ses.m_alerts.should_post<tracker_error_alert>())
 			{
 				m_ses.m_alerts.post_alert(tracker_error_alert(get_handle()
-					, ae?ae->fails:0, response_code, r.url, str));
+					, ae?ae->fails:0, response_code, r.url, ec, msg));
 			}
 		}
 		else if (r.kind == tracker_request::scrape_request)
 		{
 			if (m_ses.m_alerts.should_post<scrape_failed_alert>())
 			{
-				m_ses.m_alerts.post_alert(scrape_failed_alert(get_handle(), r.url, str));
+				m_ses.m_alerts.post_alert(scrape_failed_alert(get_handle(), r.url, ec));
 			}
 		}
 		update_tracker_timer();
diff --git a/src/tracker_manager.cpp b/src/tracker_manager.cpp
index 031f2c6de..480b6672c 100644
--- a/src/tracker_manager.cpp
+++ b/src/tracker_manager.cpp
@@ -140,10 +140,11 @@ namespace libtorrent
 		return m_requester.lock();
 	}
 
-	void tracker_connection::fail(int code, char const* msg, int interval, int min_interval)
+	void tracker_connection::fail(error_code const& ec, int code
+		, char const* msg, int interval, int min_interval)
 	{
 		boost::shared_ptr<request_callback> cb = requester();
-		if (cb) cb->tracker_request_error(m_req, code, msg
+		if (cb) cb->tracker_request_error(m_req, code, ec, msg
 			, interval == 0 ? min_interval : interval);
 		close();
 	}
@@ -158,13 +159,6 @@ namespace libtorrent
 		m_man.received_bytes(bytes);
 	}
 
-	void tracker_connection::fail_timeout()
-	{
-		boost::shared_ptr<request_callback> cb = requester();
-		if (cb) cb->tracker_request_timed_out(m_req);
-		close();
-	}
-	
 	void tracker_connection::close()
 	{
 		cancel();
@@ -246,8 +240,9 @@ namespace libtorrent
 		{
 			// we need to post the error to avoid deadlock
 			if (boost::shared_ptr<request_callback> r = c.lock())
-				ios.post(boost::bind(&request_callback::tracker_request_error, r, req, -1
-					, "unknown protocol in tracker url: " + req.url, 0));
+				ios.post(boost::bind(&request_callback::tracker_request_error, r, req
+					, -1, error_code(errors::unsupported_url_protocol)
+					, "", 0));
 			return;
 		}
 
diff --git a/src/udp_tracker_connection.cpp b/src/udp_tracker_connection.cpp
index c0d999436..4e35bf16c 100644
--- a/src/udp_tracker_connection.cpp
+++ b/src/udp_tracker_connection.cpp
@@ -97,7 +97,7 @@ namespace libtorrent
 
 		if (ec)
 		{
-			fail(-1, ec.message().c_str());
+			fail(ec);
 			return;
 		}
 		
@@ -123,7 +123,7 @@ namespace libtorrent
 		if (error == asio::error::operation_aborted) return;
 		if (error || i == udp::resolver::iterator())
 		{
-			fail(-1, error.message().c_str());
+			fail(error);
 			return;
 		}
 
@@ -152,7 +152,7 @@ namespace libtorrent
 
 		if (m_endpoints.empty())
 		{
-			fail(-1, "blocked by IP filter");
+			fail(error_code(errors::banned_by_ip_filter));
 			return;
 		}
 		
@@ -194,7 +194,7 @@ namespace libtorrent
 		m_socket.bind(udp::endpoint(bind_interface(), 0), ec);
 		if (ec)
 		{
-			fail(-1, ec.message().c_str());
+			fail(ec);
 			return;
 		}
 
@@ -231,7 +231,7 @@ namespace libtorrent
 #endif
 		m_socket.close();
 		m_name_lookup.cancel();
-		fail_timeout();
+		fail(error_code(errors::timed_out));
 	}
 
 	void udp_tracker_connection::close()
@@ -254,7 +254,7 @@ namespace libtorrent
 		if (m_target != ep) return;
 		
 		received_bytes(size + 28); // assuming UDP/IP header
-		if (e) fail(-1, e.message().c_str());
+		if (e) fail(e);
 
 #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
 		boost::shared_ptr<request_callback> cb = requester();
@@ -289,7 +289,7 @@ namespace libtorrent
 
 		if (action == action_error)
 		{
-			fail(-1, std::string(ptr, size - 8).c_str());
+			fail(error_code(errors::tracker_failure), -1, std::string(ptr, size - 8).c_str());
 			return;
 		}
 
@@ -379,7 +379,7 @@ namespace libtorrent
 		++m_attempts;
 		if (ec)
 		{
-			fail(-1, ec.message().c_str());
+			fail(ec);
 			return;
 		}
 	}
@@ -415,7 +415,7 @@ namespace libtorrent
 		++m_attempts;
 		if (ec)
 		{
-			fail(-1, ec.message().c_str());
+			fail(ec);
 			return;
 		}
 	}
@@ -433,7 +433,7 @@ namespace libtorrent
 		int num_peers = (size - 20) / 6;
 		if ((size - 20) % 6 != 0)
 		{
-			fail(-1, "invalid udp tracker response length");
+			fail(error_code(errors::invalid_tracker_response_length));
 			return;
 		}
 
@@ -495,25 +495,25 @@ namespace libtorrent
 
 		if (transaction != m_transaction_id)
 		{
-			fail(-1, "incorrect transaction id");
+			fail(error_code(errors::invalid_tracker_transaction_id));
 			return;
 		}
 
 		if (action == action_error)
 		{
-			fail(-1, std::string(buf, size - 8).c_str());
+			fail(error_code(errors::tracker_failure), -1, std::string(buf, size - 8).c_str());
 			return;
 		}
 
 		if (action != action_scrape)
 		{
-			fail(-1, "invalid action in announce response");
+			fail(error_code(errors::invalid_tracker_action));
 			return;
 		}
 
 		if (size < 20)
 		{
-			fail(-1, "got a message with size < 20");
+			fail(error_code(errors::invalid_tracker_response_length));
 			return;
 		}
 
@@ -602,7 +602,7 @@ namespace libtorrent
 		++m_attempts;
 		if (ec)
 		{
-			fail(-1, ec.message().c_str());
+			fail(ec);
 			return;
 		}
 	}