Procedure

1. Go to Administration → IMSS Configuration → SMTP Routing.
2. Click the Message Rule tab.
   The Message Rule screen appears.
3. Specify the Message Limits settings:
   • Maximum message size: Specify the number of megabytes.
   • Maximum number of recipients: Specify the number of recipients from 0 to 99999.
4. Specify the Incoming Message Settings.
   IMSS relays the messages to the added domains.

   The following shows sample content of a domain list text file:

   • domain.com: Imports the exact domain
   • *.domain.com: Imports all sub-domains
   • domain.org: Imports the exact domain
5. Specify the Permitted Senders of Relayed Mail.
   • Host only
   • Same subnet as the host
   • Same IP class as the host
   • Specified IP addresses
6. Click Save.

   Tip For security reasons, Trend Micro recommends avoiding open relay when configuring the message rule settings.