Smartlead lets you assign SmartInfra to clients for exclusive use, keeping their email-sending infrastructure completely isolated from other clients.
This guide walks you through assigning SmartInfra to an existing client.
Log in to your Smartlead account.
Click on Client Portal from the left-hand menu

From the list of clients, choose the one you want to assign SmartInfra to.
Click on the client's name to open their settings.
In the client's settings, scroll to the Private Infrastructure section.

You'll see two drop downs:
Multi SmartInfra - select a bundle to assign
Single Server - select an individual dedicated server to assign
Click Update to save your changes.
Exclusive usage: once a SmartInfra (Single or Multi) is assigned to a client, it can't also be assigned to a different client.
No cap on multiples: a client can hold multiple Single SmartInfra, or multiple Multi SmartInfra bundles, with no limit.
Campaign-level flexibility: SmartInfra assigned to a client can still be allocated across multiple campaigns within that client's account.
Per the mutual-exclusivity rule for SmartInfra, a client should be on either Single SmartInfra or Multi SmartInfra, not both at once.