Indeed, if you use a load-balancer in the traditional way, the SMTP relay service will understand that all messages come from the balancer.
the proxy protocol was developed to maintain client information when chaining proxies and reverse-proxies.
This technique has been extended to the SMTP protocol.
This feature is available on Artica v4.40 Service pack 28 or above.
Two main advantages when using it:
So you need first to be sure that your load balancer is “Proxy Protocol aware”
Note: This method aims to initialize a dedicated communication with the load balancer.
Also, it will no longer be possible to connect directly to the SMTP service.
You will have to use the load balancer to communicate with the SMTP port
On the main parameters of your SMTP service, turn on the option “Activate Load-balancer compliance” and click on apply button.