We are deploying Teams in an organization and need to decide on Guest access vs External Access.
So from what I understand.
External Access is for other organizations with an O365 Tenant
Guest Access is for external domains whether they have a tenant or not.
Since you can just add guests why would you bother with external access in MS Teams? I know you can allow certain domains and block them but from what iI understand you can also block and allow guest domains in Azure.
External access (federation) and guest access are different:
Guest access gives access permission to an individual. External access gives access permission to an entire domain.
Guest access, once granted by a team owner, allows a guest to access resources, such as channel discussions and files, for a specific team, and chat with other users in the team they have been invited to. With external access (federated chat), the external chat participants have no access to the inviting organization’s teams or team resources. They can only participate in one-on-one federated chat. Tenant admins can choose between the two communication options depending on which level of collaboration is desirable with the external party. Admins can choose either approaches or both, depending on their organizational needs, but we recommend enabling guest access for a fuller, collaborative Teams experience.
With external access you can do whole domains: quicker and easier to implement between two organisations. However, guest seem to be becoming the more typical way to add users outside the organisation.
External is just chat! Like Skype for business! They are not part of your team and don’t have to switch tenant to reach reach out! Federation ( external) is basically for communication and guest access is best suited for collaboration