Prefilter MTA global security policies for incoming emails:
- Maximum message size including attachments: 50MB
- Maximum number of recipients: 1000
- Maximum layers of compression for attachments: 19
- Maximum number of files in compressed attachments: 300
- Delivery retry interval starts from 60 seconds with retry multiplier of 1.5. Therefore, retry interval will increase by half for every delivery attempt. i.e. 60, 90, 135…
- The maximum retry interval is 3600 seconds.
- The maximum time a message stays in the retry queue is 5 days. Before that timeout, the message will be redelivered with retry interval. Afterwards, the message will be removed from the queue and the sender will receive an NDR message.