Choosing the operation mode
Once the FortiMail unit is mounted and powered on, and you have completed initial configuration, you can configure the operation mode of the FortiMail unit using the CLI or web UI.
FortiMail units can run in one of three operation modes: gateway mode, transparent mode, or server mode. Requirements of each operation mode vary.
Table 6: Comparison of gateway, transparent, and server mode of operation
| Gateway | Transparent | Server | |
| SMTP role | MTA/relay | Transparent proxy/relay | Server |
| FortiMail unit is hidden | No | Yes, if enabled | No |
| Email user accounts | Preferences and per-recipient quarantine only | Preferences and per-recipient quarantine only | Yes |
| Requires DNS record change | Yes | No, if hidden with no per-recipient quarantines or Bayesian scan | Yes |
Table 6: Comparison of gateway, transparent, and server mode of operation
| May require changes to SMTP client configurations or other infrastructure | Yes | No | Yes |
| Requires FortiMail unit located between external MTAs and protected email servers | No | Yes | N/A
(FortiMail unit acts as email server) |
| Protected email servers | Separate | Separate | Integrated
(FortiMail unit acts as email server) |
In addition, some FortiMail features are specific to the operation mode. As a result, changing the operation mode may reset your FortiMail configuration.
You will usually choose the operation mode that is appropriate for your topology and requirements and configure the operation mode only once, just after physical installation and initial configuration, and before using the Quick Start Wizard.
This section describes each operation mode, assisting you in choosing the mode that best suits your requirements.
This section contains the following topics:
- Deployment guidelines
- Characteristics of gateway mode
- Characteristics of transparent mode
- Characteristics of server mode
- Changing the operation mode