diff --git a/modoboa_installer/scripts/files/postfix/main.cf.tpl b/modoboa_installer/scripts/files/postfix/main.cf.tpl
index 7af5487..0123e60 100644
--- a/modoboa_installer/scripts/files/postfix/main.cf.tpl
+++ b/modoboa_installer/scripts/files/postfix/main.cf.tpl
@@ -3,7 +3,7 @@ inet_protocols = all
 myhostname = %hostname
 myorigin = $myhostname
 mydestination = $myhostname
-mynetworks = 127.0.0.0/8
+mynetworks = 127.0.0.0/8 [::1]/128
 smtpd_banner = $myhostname ESMTP
 biff = no
 unknown_local_recipient_reject_code = 550