How To: Limit Incoming SMTP Email Size On MDaemon Mail Server

Sometime it is necessary to limit outgoing email size for you who have a limited bandwidth, especially for Indonesian :D. Being honest folks, the price for bandwidth is expensive here. It can be a nightmare for companies with crowded email traffic.

I use MDaemon to either send or download emails (from the web hosting provider) for company and distribute them to local mail account. The advantage of using this method is to avoid high internet traffic in the morning and to use unused bandwidth after office hour.

Office staff sends email trough MDaemon which is available on LAN and MDaemon will relay the email to company’s SMTP account in the web hosting provider. It will safe staff from waiting email to be sent (yes, because of using LAN connection) rather than sends directly to hosted SMTP.

Without prediction, this method kicked me back. Put me in a problem. Because the connection between client and MDaemon SMTP server is using LAN, then all email with any size can be sent to MDaemon in a blink of eyes, even a 50MB email 🙁
Searched on Google, pointed me to this web.Here is a step by step on how to limit incoming SMTP email size on MDaemon Mail Server:

1. Click Security -> Content Filter
2. Click New Rule button
3. Give a name for Rule, e.g.: Limit Incoming SMTP
4. Check option “If the MESSAGE SIZE is greater than”
5. Click link “is greater than ‘10k’” (with blue color in Rule Description) and enter the maximum email size that allowed to send trough SMTP, e.g.: 1500.
6. Check option “Send a note 1 to …”
7. Click link “specify information” (with blue color in Rule Description)  and enter “$SENDER$” in the To field, “[REJECTED] $SUBJECT$” in the Subject field dan type your notification message in the Message Text. If you want to include the original message, check option “Include the original message”. Click OK.
8. Check option “Delete the message”
9. Klik OK to save Rule.
10. Done

That’s it.

Now every staff can only send email with 1.5 MB in size. The next thing you should do is monitoring the log and MDaemon outgoing email queue.