diff --git a/Transmission.xcodeproj/project.pbxproj b/Transmission.xcodeproj/project.pbxproj
index 77f17f7e1..2e4c64535 100644
--- a/Transmission.xcodeproj/project.pbxproj
+++ b/Transmission.xcodeproj/project.pbxproj
@@ -1600,6 +1600,7 @@
 			isa = PBXNativeTarget;
 			buildConfigurationList = BE11834C0CE160A80002D0F3 /* Build configuration list for PBXNativeTarget "miniupnp" */;
 			buildPhases = (
+				A2305097100C0293003FDB0C /* ShellScript */,
 				BE1183440CE160960002D0F3 /* Headers */,
 				BE1183450CE160960002D0F3 /* Sources */,
 				BE1183460CE160960002D0F3 /* Frameworks */,
@@ -1826,6 +1827,19 @@
 			shellPath = /bin/sh;
 			shellScript = "sh update-version-h.sh";
 		};
+		A2305097100C0293003FDB0C /* ShellScript */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputPaths = (
+			);
+			outputPaths = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "cd ./third-party/miniupnp/\nsh updateminiupnpcstrings.sh";
+		};
 		BE75C3510C729EE100DBEFE0 /* ShellScript */ = {
 			isa = PBXShellScriptBuildPhase;
 			buildActionMask = 2147483647;
diff --git a/third-party/miniupnp/Makefile.am b/third-party/miniupnp/Makefile.am
index cd5e8c7b8..f86497694 100644
--- a/third-party/miniupnp/Makefile.am
+++ b/third-party/miniupnp/Makefile.am
@@ -20,7 +20,6 @@ noinst_HEADERS = \
     minisoap.h \
     minissdpc.h \
     miniupnpc.h \
-    miniupnpcstrings.h \
     miniwget.h \
     minixml.h \
     upnpcommands.h \
diff --git a/third-party/miniupnp/miniupnpcstrings.h b/third-party/miniupnp/miniupnpcstrings.h
index 4018b3b22..4c38dd449 100644
--- a/third-party/miniupnp/miniupnpcstrings.h
+++ b/third-party/miniupnp/miniupnpcstrings.h
@@ -8,7 +8,7 @@
 #ifndef __MINIUPNPCSTRINGS_H__
 #define __MINIUPNPCSTRINGS_H__
 
-#define OS_STRING "RedHatEnterpriseClient/5.3"
+#define OS_STRING "Darwin/9.7.0"
 #define MINIUPNPC_VERSION_STRING "1.3"
 
 #endif
diff --git a/third-party/miniupnp/miniupnpcstrings.h.in b/third-party/miniupnp/miniupnpcstrings.h.in
new file mode 100644
index 000000000..be060cc88
--- /dev/null
+++ b/third-party/miniupnp/miniupnpcstrings.h.in
@@ -0,0 +1,15 @@
+/* $Id: miniupnpcstrings.h.in,v 1.1 2009/07/09 16:13:31 nanard Exp $ */
+/* Project: miniupnp
+ * http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
+ * Author: Thomas Bernard
+ * Copyright (c) 2005-2009 Thomas Bernard
+ * This software is subjects to the conditions detailed
+ * in the LICENCE file provided within this distribution */
+#ifndef __MINIUPNPCSTRINGS_H__
+#define __MINIUPNPCSTRINGS_H__
+
+#define OS_STRING "OS/version"
+#define MINIUPNPC_VERSION_STRING "1.3"
+
+#endif
+
diff --git a/third-party/miniupnp/updateminiupnpcstrings.sh b/third-party/miniupnp/updateminiupnpcstrings.sh
new file mode 100755
index 000000000..7f05310ac
--- /dev/null
+++ b/third-party/miniupnp/updateminiupnpcstrings.sh
@@ -0,0 +1,37 @@
+#! /bin/sh
+# $Id: updateminiupnpcstrings.sh,v 1.3 2009/07/09 16:13:31 nanard Exp $
+
+FILE=miniupnpcstrings.h
+
+# detecting the OS name and version
+OS_NAME=`uname -s`
+OS_VERSION=`uname -r`
+if [ -f /etc/debian_version ]; then
+	OS_NAME=Debian
+	OS_VERSION=`cat /etc/debian_version`
+fi
+# use lsb_release (Linux Standard Base) when available
+LSB_RELEASE=`which lsb_release`
+if [ 0 -eq $? ]; then
+	OS_NAME=`${LSB_RELEASE} -i -s`
+	OS_VERSION=`${LSB_RELEASE} -r -s`
+	case $OS_NAME in
+		Debian)
+			#OS_VERSION=`${LSB_RELEASE} -c -s`
+			;;
+		Ubuntu)
+			#OS_VERSION=`${LSB_RELEASE} -c -s`
+			;;
+	esac
+fi
+
+echo "Detected OS [$OS_NAME] version [$OS_VERSION]"
+
+EXPR="s/OS_STRING \".*\"/OS_STRING \"${OS_NAME}\/${OS_VERSION}\"/"
+#echo $EXPR
+#echo "Backuping $FILE to $FILE.bak."
+#cp $FILE $FILE.bak
+test -f ${FILE}.in
+echo "setting OS_STRING macro value to ${OS_NAME}/${OS_VERSION} in $FILE."
+cat ${FILE}.in | sed -e "$EXPR" > $FILE
+