diff --git a/bin/v-make-separated-ip-for-email b/bin/v-make-separated-ip-for-email
index 6ca4343b..69c8565b 100644
--- a/bin/v-make-separated-ip-for-email
+++ b/bin/v-make-separated-ip-for-email
@@ -40,7 +40,7 @@ fi
 #                    Verifications                         #
 #----------------------------------------------------------#
 
-check_args '2' "$#" 'MAIL_HOSTNAME MAIL_IP'
+check_args '2' "$#" 'MAIL_HOSTNAME MAIL_IP [NETMASK]'
 is_domain_format_valid "$MAIL_HOSTNAME"
 is_ip_format_valid "$MAIL_IP"