diff --git a/opendkim/files/opendkim-add.sh b/opendkim/files/opendkim-add.sh
index a7da1ce0..fa663a59 100644
--- a/opendkim/files/opendkim-add.sh
+++ b/opendkim/files/opendkim-add.sh
@@ -1,5 +1,13 @@
 #!/bin/sh
 
+
+dpkg -l |grep -e 'opendkim-tools' -e 'opendkim' -q
+
+if [ "$?" -ne 0 ]; then 
+    echo "Require opendkim-tools and opendkim"
+    exit 1
+fi
+
 if [ "$#" -ne 1 ]; then
     echo "Usage : $0 example.com" >&2
     exit 1