diff --git a/include/libtorrent/escape_string.hpp b/include/libtorrent/escape_string.hpp
index 6e65a827d..f818f3bc8 100644
--- a/include/libtorrent/escape_string.hpp
+++ b/include/libtorrent/escape_string.hpp
@@ -61,6 +61,8 @@ namespace libtorrent
 	// it will be encoded
 	std::string TORRENT_EXPORT maybe_url_encode(std::string const& url);
 
+	bool TORRENT_EXPORT need_encoding(char const* str, int len);
+
 	// encodes a string using the base64 scheme
 	TORRENT_EXPORT std::string base64encode(std::string const& s);
 	TORRENT_EXPORT std::string base64decode(std::string const& s);
diff --git a/src/escape_string.cpp b/src/escape_string.cpp
index f8c117ff3..34f192f67 100644
--- a/src/escape_string.cpp
+++ b/src/escape_string.cpp
@@ -179,10 +179,19 @@ namespace libtorrent
 
 	// http://www.ietf.org/rfc/rfc2396.txt
 	// section 2.3
-	// some trackers seems to require that ' is escaped
-	static const char unreserved_chars[] = "%'/-_.!~*()"
+	static const char unreserved_chars[] =
+		// when determining if a url needs encoding
+		// % should be ok
+		"%+"
+		// reserved
+		";?:@=&/"
+		// unreserved (special characters) ' excluded,
+		// since some buggy trackers fail with those
+		"$-_.!~*(),"
+		// unreserved (alphanumerics)
 		"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
 		"0123456789";
+
 	static const char hex_chars[] = "0123456789abcdef";
 
 	// the offset is used to ignore the first characters in the unreserved_chars table.
@@ -213,15 +222,15 @@ namespace libtorrent
 	
 	std::string escape_string(const char* str, int len)
 	{
-		return escape_string_impl(str, len, 3);
+		return escape_string_impl(str, len, 9);
 	}
 
 	std::string escape_path(const char* str, int len)
 	{
-		return escape_string_impl(str, len, 2);
+		return escape_string_impl(str, len, 8);
 	}
 
-	static bool need_encoding(char const* str, int len)
+	bool need_encoding(char const* str, int len)
 	{
 		for (int i = 0; i < len; ++i)
 		{
diff --git a/test/test_primitives.cpp b/test/test_primitives.cpp
index a2bbb0e6e..2a7739221 100644
--- a/test/test_primitives.cpp
+++ b/test/test_primitives.cpp
@@ -519,6 +519,31 @@ int test_main()
 	TEST_CHECK(*url_has_argument("http://127.0.0.1/test?foo=24&bar=23&a=e", "a") == "e");
 	TEST_CHECK(!url_has_argument("http://127.0.0.1/test?foo=24&bar=23&a=e", "b"));
 
+	// escape_string
+	char const* test_string = "!@#$%^&*()-_=+/,. %?";
+	TEST_CHECK(escape_string(test_string, strlen(test_string))
+		== "!%40%23$%25%5e%26*()-_%3d%2b%2f,.%20%25%3f");
+
+	// escape_path
+	TEST_CHECK(escape_path(test_string, strlen(test_string))
+		== "!%40%23$%25%5e%26*()-_%3d%2b/,.%20%25%3f");
+
+	// need_encoding
+	char const* test_string2 = "!@$&()-_/,.%?";
+	TEST_CHECK(need_encoding(test_string, strlen(test_string)) == true);
+	TEST_CHECK(need_encoding(test_string2, strlen(test_string2)) == false);
+	TEST_CHECK(need_encoding("\n", 1) == true);
+
+	// maybe_url_encode
+	TEST_CHECK(maybe_url_encode("http://bla.com/\n") == "http://bla.com:80/%0a");
+	std::cerr << maybe_url_encode("http://bla.com/\n") << std::endl;
+	TEST_CHECK(maybe_url_encode("?&") == "?&");
+
+	// unescape_string
+	TEST_CHECK(unescape_string(escape_string(test_string, strlen(test_string)), ec)
+		== test_string);
+	std::cerr << unescape_string(escape_string(test_string, strlen(test_string)), ec) << std::endl;
+
 	// HTTP request parser
 
 	http_parser parser;