A continuous common issue we have seen is mass sending of unsolicited email by invalid users using legitimate customer’s email account information.
Once the mail account that is used for SMTP authentication is stolen, particularly by means of some sort of virus infection, etc., third party users take over an account and use the email address to mass-distribute their spam/malware. This results in legitimate email sent by our customer to be rejected as junk email at the destination server.
We have already taken action to implement the Rate-Limit Restriction to prevent and reduce the above mentioned cases.
In order to ensure the delivery of our customer’s legitimate email more effectively, we are implementing a limit for sending email as described below.
Implementation Summary :
- Total amount of sending email per account will be a maximum of 1000 emails in 24 hours. If the system detects over 1000 emails from an individual account, temporary suspension of sending email will occur. Service will resume automatically after the system resets the counter.
- The system starts counting the sending email from 00:00 to 24:00 JST, and resets the counter at 00:00 JST every day.
- If a message includes some destination addresses, (in any address line including To, CC, BCC), each recipient is regarded as 1 email.
- For example, the message has 100 destination addresses is counted as 100 emails.
- This restriction will not affect receiving email.
- In case emails are sent from the countries where mass sending of unsolicited email have occurred in the past, the sending suspension will occasionally apply for less than 1000 emails.