Chapter 4 FortiOS Carrier : Message flood protection : Notifying message flood senders and receivers : Responses to MM1 senders and receivers
  
Responses to MM1 senders and receivers
When the FortiOS Carrier unit identifies an MM1 message sent by a sender to an MMSC as a flood message and blocks it, the FortiOS Carrier unit returns a message submission confirmation (m-send.conf) to the sender — otherwise the sender’s handset would keep retrying the message. The m‑send.conf message is sent only when the MM1 message flood action is set to Block. For other message flood actions the message is actually delivered to the MMSC and the MMSC sends the m-send.conf message.
You can customize the m-send.conf message by editing the MM1 send-conf flood message MM1 replacement message (from the CLI the mm1-send-conf-flood replacement message). You can customize the response status and message text for this message. The default response status is “Content not accepted”. To hide the fact that FortiOS Carrier is responding to a flood, you can change the response status to “Success”. The default message text informs the sender that the message was blocked. You could change this to something more generic.
For example, the following command sets the submission confirmation response status to “Success” and changes the message text to “Message Sent OK”:
config system replacemsg mm1 mm1-send-conf-flood
set rsp-status ok
set rsp-text “Message Sent OK”
end
When the FortiOS Carrier unit identifies an MM1 message received by a receiver from an MMSC as a flood message and blocks it, the FortiOS Carrier unit returns a message retrieval confirmation (m-retrieve.conf) to the sender (otherwise the sender’s handset would keep retrying the message). The m‑retrieve.conf message is sent only when the MM1 message flood action is set to Block. For other message flood actions the message is actually delivered to the receiver, so the MMSC sends the m-retrieve.conf message.
You can customize the m-retrive.conf message by editing the MM1 retrieve-conf flood message MM1 replacement message (from the CLI the mm1-retr-conf-flood replacement message). You can customize the class, subject, and message text for this message.
For example, you could use the following command make the response more generic:
config system replacemsg mm1 mm1-retr-conf-flood
set subject “Message blocked”
set message “Message temporarily blocked by carrier”
end