the DIY RECIPE for
You need to establish a way to control guest access to Teams.
You get complete instruction on how to build your own solution for governing Guest Access to your Microsoft 365 Tenant.
Included is PowerShell scripts utilizing the Hexatown.com framework for interacting with your tenant. You also get a SharePoint Communication site with all the SharePoint lists required for managing guest as well as a PowerApps application for import into your tenant.
The solution use no premium features from the Power platform and do not consume Power Automate Actions.
You can even host the logic on your own servers to avoid spending any additional costs. We recommend that you spin up your Azure Web App for hosting the logic using Azure Functions.
Build a SharePoint lists with all your guest users
Build a SharePoint lists with all domains of guest users
Process logic for managing changes to guests and domains
Track ownership of domains and guests
Ability to prevent guest from blacked listed domains to get access
Ability to disabling existing guest access is you blacklist a domain
Routine for disabling guest users on expiration date
Routine for deleting guest users