diff --git a/Shorewall/Perl/prog.footer6 b/Shorewall/Perl/prog.footer6
index f41bef680..f7b458983 100644
--- a/Shorewall/Perl/prog.footer6
+++ b/Shorewall/Perl/prog.footer6
@@ -79,7 +79,7 @@ COMMAND="$1"
 
 [ -n "${PRODUCT:=Shorewall6}" ]
 
-kernel=$(printf "%2d%02d%02d\n" $(echo $(uname -r) 2> /dev/null | sed 's/-.*//' | tr '.' ' ' ) | head -n1)
+kernel=$(printf "%2d%02d%02d" $(uname -r 2> /dev/null | sed -e 's/-.*//' -e 's/^\([0-9][0-9]*\)\.\([0-9][0-9]*\)\.\([0-9][0-9]*\).*$/\1 \2 \3/g'))
 if [ $kernel -lt 20624 ]; then
     error_message "ERROR: $PRODUCT requires Linux kernel 2.6.24 or later"
     status=2