Note that external sharing is turned on by default for your entire Office 365 environment. Every user can invite external people to Groups, Teams and SharePoint sites and can share content using OneDrive for Business. You may want to turn it off globally until you know exactly how you want to use the feature.Poorly there is no mater switch to turn external sharing and inviting external user ON or OFF globally. We need to configure it per service and there are also cross sites effects between the services.
External sharing overview
When sharing a SharePoint site with an authenticated external user, an invitation is sent to them via email which contains a link to the site. During the login process they are asked to log in using the username and password of their Microsoft account or their work or school account. If the login is successful, the account is added to the Azure AD associated to the Office 365 subscription. The account is added with #EXT# in the user name.
An external user did not need to have a license. To discontinue sharing with an authenticated external user, remove the permissions from the site or delete the user in the Azure AD.
If you share a file or folder with an external user, this user gets an email with a link to the file or folder. The user gets a time-sensitive code via email that he can use to verify his identity. Once he proved his identity by using the code the user is added as a external user in the Azure AD and he can access the file using his account. Sharing a file or folder with a user that did not have a Microsoft account or work or school account this user needs to use the code every time to access the shared content.
To discontinue sharing with an authenticated external user you can delete the sharing link that was sent to him.
To share with anonymous users, you can set several options:
- Edit, view or upload to a folder
- Set link to expire at a specified time
- Block download
The (external) user will receive a E-Mail with the link to the file or folder.Anonymous users are not added to the Azure AD. To discontinue sharing you need to delete the anonymous link.
Guest access on the collaboration level is included with all Office 365 Business Premium, Office 365 Enterprise, and Office 365 Education subscriptions. No additional licensing for the guest users is requirement. You can have up to 5 guests per licensed user on your tenant. For more information about licensing, see Azure Active Directory B2B collaboration licensing guidance.
Office 365 Groups
To collaborate with external users in your Office 365 Group this feature must be activated as showed in the table above. By default, guest access is turned on in Office 365. That means, that everyone in your organization can add external users to an Office 365 Group. When an external user is invited to join a group, he receives an invitation email. The external user will have access to the following Office 365 Group features:
- Conversations: Externals did not get access to the conversation history, but they will become part of the Office 365 Group distribution list.
- Notebook: Externals get access to OneNote
- Calendar: No access, but they receive calendar invitations
- SharePoint Team Site: Externals get access to the SharePoint Team Site
- Planner: To access a plan, guests either need to use a specific plan URL or go to https://tasks.office.com/%organizationdomainname%
Because of Microsoft Teams is using services like SharePoint Online etc. the external access configuration belongs on the settings in you tenant.
Each level controls the guest access as shown:
- Azure Active Directory: External access in Microsoft Teams relies on Azure AD.
- Microsoft Teams: Controls external access in Microsoft Teams.
- Office 365 Groups: Controls external access in Office 365 Groups and Microsoft Teams.
- SharePoint Online and OneDrive for Business: Controls external access in SharePoint Online and OneDrive for Business.
Office 365 inter-tenant collaboration
We have several options to collaborate between two Office 365 tenants. Based on Azure Active Directory B2B we can set up collaboration for nearly all Office 365 services. Details are described in this Microsoft article: Office 365 inter-tenant collaboration
Tenant restrictions enables you to control access to other Office 365 tenants. Tenant restrictions gives organizations the ability to specify the list of tenants that their users are permitted to access. Details, pre-requirements and limitations are described in this Microsoft article: Use Tenant Restrictions to manage access to SaaS cloud applications
Office 365 user vs. Windows Live ID
Anyone with a Microsoft work or school account or a consumer email account, such as Outlook, Gmail, or others, can participate as a guest in Office 365.
If a user has an Office 365 hosted E-Mail address, he will automatically have a work or school account created by his IT department. This account original exists in an Azure AD.
If a user does not have a work or school account, he can use a LiveID. To get one the user needs to go to the Microsoft account sign-in page: https://account.microsoft.com/. In the upper right corner select “Login” and then select “No account”. He needs to fill out the form and create a password. Details see below in “Coaching your (guest) users through the External Sharing Experience” The LiveID is original hosted by Microsoft.
Coaching your (guest) users through the External Sharing Experience
IF you are inviting an external user to a SharePoint site or added him to a SharePoint group, he will receive an invitation E-Mail:
The link in the email will point the user to a website asking him what type of account he has:
If the user enters his email but did not have a Microsoft account, he will see the following dialog:
Click “Create One!” to register a new Microsoft account:
Set a password:
Provide your details:
Microsoft will send a code to verify the email address:
If a file or folder in SharePoint or OneDrive for Business is shared to an external user and the user did not already exists in the Azure AD, he will also need to verify his E-Mail address:
Sharing a file or folder with a user that did not have a Microsoft work or school account this user needs to use the code every time to access the shared content.
When an external user is invited to a group, he receives an E-Mail:
External member's can join conversations through their inbox and receive calendar invitations.
When an external user is invited to a group, he also receives an E-Mail with the details: