--- Documents/01ifupdown	2015-04-17 22:04:55.000000000 +0300
+++ 01ifupdown	2015-05-17 17:14:33.000000000 +0300
@@ -47,11 +47,21 @@
             export MODE="start"
             export PHASE="post-up"
             run-parts /etc/network/if-up.d
+            if [ -z "$1" ]; then
+             echo "$0: called with no interface" 1>&2
+             exit 2;
+            fi
+
             ;;
         down|vpn-down)
             export MODE="stop"
             export PHASE="post-down"
             run-parts /etc/network/if-post-down.d
+            if [ -z "$1" ]; then
+             echo "$0: called with no interface" 1>&2
+            exit 3;
+            fi
+
             ;;
 # pre-up/pre-down not implemented. See
 # https://bugzilla.gnome.org/show_bug.cgi?id=387832