diff --git a/Shorewall-init/install.sh b/Shorewall-init/install.sh
index 8683171c9..3a9d0d090 100755
--- a/Shorewall-init/install.sh
+++ b/Shorewall-init/install.sh
@@ -88,9 +88,6 @@ install_file() # $1 = source $2 = target $3 = mode
 
 [ -n "$DESTDIR" ] || DESTDIR="$PREFIX"
 
-#
-# Parse the run line
-#
 # DEST is the SysVInit script directory
 # INIT is the name of the script in the $DEST directory
 # ARGS is "yes" if we've already parsed an argument
@@ -125,6 +122,15 @@ done
 PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin:/usr/local/sbin
 
 [ -n "${LIBEXEC:=/usr/share}" ]
+
+case "$LIBEXEC" in
+    /*)
+	;;
+    *)
+	LIBEXEC=/usr/${LIBEXEC}
+	;;
+esac
+
 #
 # Determine where to install the firewall script
 #
diff --git a/Shorewall-lite/install.sh b/Shorewall-lite/install.sh
index 6e408fc6d..c430b9014 100755
--- a/Shorewall-lite/install.sh
+++ b/Shorewall-lite/install.sh
@@ -124,6 +124,15 @@ done
 PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin:/usr/local/sbin
 
 [ -n "${LIBEXEC:=/usr/share}" ]
+
+case "$LIBEXEC" in
+    /*)
+	;;
+    *)
+	LIBEXEC=/usr/${LIBEXEC}
+	;;
+esac
+
 #
 # Determine where to install the firewall script
 #
diff --git a/Shorewall/install.sh b/Shorewall/install.sh
index 8e7a21e22..75703133d 100755
--- a/Shorewall/install.sh
+++ b/Shorewall/install.sh
@@ -110,6 +110,22 @@ MANDIR=${MANDIR:-"/usr/share/man"}
 [ -n "${LIBEXEC:=/usr/share}" ]
 [ -n "${PERLLIB:=/usr/share/shorewall}" ]
 
+case "$LIBEXEC" in
+    /*)
+	;;
+    *)
+	LIBEXEC=/usr/${LIBEXEC}
+	;;
+esac
+
+case "$PERLLIB" in
+    /*)
+	;;
+    *)
+	PERLLIB=/usr/${PERLLIB}
+	;;
+esac
+
 INSTALLD='-D'
 
 case $(uname) in
diff --git a/Shorewall6-lite/install.sh b/Shorewall6-lite/install.sh
index e41f54746..31f913c4a 100755
--- a/Shorewall6-lite/install.sh
+++ b/Shorewall6-lite/install.sh
@@ -124,6 +124,15 @@ done
 PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin:/usr/local/sbin
 
 [ -n "${LIBEXEC:=/usr/share}" ]
+
+case "$LIBEXEC" in
+    /*)
+	;;
+    *)
+	LIBEXEC=/usr/${LIBEXEC}
+	;;
+esac
+
 #
 # Determine where to install the firewall script
 #
diff --git a/Shorewall6/install.sh b/Shorewall6/install.sh
index 620cd18a5..54a35f14d 100755
--- a/Shorewall6/install.sh
+++ b/Shorewall6/install.sh
@@ -113,6 +113,22 @@ INSTALLD='-D'
 [ -n "${LIBEXEC:=/usr/share}" ]
 [ -n "${PERLLIB:=/usr/share/shorewall}" ]
 
+case "$LIBEXEC" in
+    /*)
+	;;
+    *)
+	LIBEXEC=/usr/${LIBEXEC}
+	;;
+esac
+
+case "$PERLLIB" in
+    /*)
+	;;
+    *)
+	PERLLIB=/usr/${PERLLIB}
+	;;
+esac
+
 case $(uname) in
     CYGWIN*)
 	if [ -z "$DESTDIR" ]; then