diff --git a/src/string_util.cpp b/src/string_util.cpp
index b2984aaba..5d53a3baf 100644
--- a/src/string_util.cpp
+++ b/src/string_util.cpp
@@ -272,8 +272,15 @@ namespace libtorrent
 			while (start < in.size() && is_digit(in[start]) && in[start] != ',')
 				port += in[start++];
 
-			if (port.empty()) iface.port = -1;
-			else iface.port = std::atoi(port.c_str());
+			if (port.empty() || port.size() > 5)
+			{
+				iface.port = -1;
+			}
+			else
+			{
+				iface.port = std::atoi(port.c_str());
+				if (iface.port <= 0 || iface.port > 65535) iface.port = -1;
+			}
 
 			// skip spaces
 			while (start < in.size() && is_space(in[start]))
diff --git a/test/Jamfile b/test/Jamfile
index 04769668b..025eebb05 100644
--- a/test/Jamfile
+++ b/test/Jamfile
@@ -206,6 +206,7 @@ test-suite libtorrent :
 # transitioned into simulations
 alias win-tests :
 	test_primitives
+	test_string
 	test_dht
 	test_sha1_hash
 	test_bitfield