Technical Tip: How to check and set a maximum number of concurrent SMTP connections supported by FortiMail

[jpatel]

Description
This article describes how to check and set a maximum number of concurrent SMTP connections supported by different FortiMail appliances, including virtual appliance.
This value may vary based on the FortiMail appliance model and firmware version.

Solution
Use the following CLI command to check the maximum number of concurrent SMTP connections supported by a particular FortiMail appliance:

# config system mailserver
# set smtp-max-connections ?
 <integer>    maximum number of concurrent smtp connections

--- current value ---
smtp-max-connections:  512                                                   <----- This value displays the current settings

valid range:  1 – 2048                                                       <----- The higher range value 2048 displays the maximum concurrent smtp connections supported by FortiMail.

Use the following CLI command to set the maximum number of concurrent SMTP connections allowed:

# config system mailserver
# set smtp-max-connections <x>                                               <------ x is the value to be set
# end

Note : Be sure that FortiMail can absorb the additional system load (cpu/memory/diskio), otherwise it is recommended to keep the default settings.