diff --git a/postinst b/postinst
index 62bbbfd..30a8d4e 100644
--- a/postinst
+++ b/postinst
@@ -3,8 +3,21 @@
 # Postinst script for authentic2-supann
 #
 
+add_supann_in_default() {
+	cat << EODEFAULT >> /etc/default/authentic2
+if [ -r /etc/authentic2/supann.conf ]; then
+	. /etc/authentic2/supann.conf
+fi
+EODEFAULT
+}
+
 case "$1" in
     configure|reconfigure)
+	if [ ! -f /etc/default/authentic2 ]; then
+		add_supann_in_default
+	elif ! grep -q supann.conf /etc/default/authentic2 2> /dev/null; then
+		add_supann_in_default
+	fi
 	invoke-rc.d authentic2 restart
 	;;
     abort-upgrade|abort-remove|abort-deconfigure)