diff --git a/base.yml b/base.yml
index 959c0774..6d88d865 100644
--- a/base.yml
+++ b/base.yml
@@ -80,6 +80,7 @@
   vars:
     mail_root: root@crans.org
     mail_snmp_server: smtp.adm.crans.org
+    mail_defaulthost: crans.org
   roles:
     - nullmailer
 
diff --git a/roles/nullmailer/tasks/main.yml b/roles/nullmailer/tasks/main.yml
index c6ea4853..9e2af7f7 100644
--- a/roles/nullmailer/tasks/main.yml
+++ b/roles/nullmailer/tasks/main.yml
@@ -16,3 +16,9 @@
   copy:
     content: "{{ mail_root }}"
     dest: /etc/nullmailer/adminaddr
+
+- name: Set nullmailer defaulthost
+  copy:
+    content: "{{ mail_defaulthost }}"
+    dest: /etc/nullmailer/defaulthost
+