Sharing & External Access Policies
MS-102 Exam Alignment
MS-102
Manage SharePoint Online sharing and external access: Configure the tenant-wide sharing level, per-site sharing overrides, domain restrictions, sharing link types and expiry, and OneDrive sharing controls.
- Know the four external sharing levels in order from most to least permissive: Anyone → New and existing guests → Existing guests → Only people in your org
- Know that the tenant-level sharing setting is the ceiling — individual sites can only be more restrictive than the tenant level, never more permissive
- Know that Anyone links (anonymous links) do not create a guest account in Entra ID — anyone with the link can access the content without signing in
- Know that enabling external sharing at the tenant level does NOT automatically enable external sharing on existing sites — site-level settings must be checked separately
🔗 The Four External Sharing Levels
| Level | Who Can Access Shared Content | Entra Guest Account Created? | Sign-In Required? |
|---|---|---|---|
| Anyone | Anyone who has the link — even if they don’t have a Microsoft account. This is anonymous sharing (also called “Anyone links”) | ❌ No — no identity verification | ❌ No — link works without authentication |
| New and existing guests | External users who are invited for the first time (new guests) OR who are already in the directory (existing guests) | ✅ Yes — new guest accounts are created in Entra ID on first access | ✅ Yes — guests must sign in |
| Existing guests only | Only external users who already have a guest account in your Entra ID directory — no new guests can be invited | ❌ No new guests — existing only | ✅ Yes |
| Only people in your organisation | No external sharing at all — content can only be shared with users inside the organisation | ❌ No external users | ✅ Internal users only |
⚠️ “Anyone” Links — The Anonymous Sharing Risk
When a user creates an “Anyone” link and shares it via email, anyone who receives that email (or if the link is forwarded) can access the content — no Microsoft account required, no sign-in, no audit trail of who accessed it. For this reason, most organisations either disable “Anyone” links entirely or configure them to expire automatically (7–30 days) and restrict link holders to view-only.
🏗️ Tenant vs Site Sharing Level — The Hierarchy
The tenant-level sharing setting (Policies → Sharing) is the maximum ceiling. Individual sites can only be set to an equal or more restrictive level.
🔐 Sharing Link Types
| Link Type | Who Can Access | Authentication Required? | Admin Controls |
|---|---|---|---|
| Anyone (anonymous) | Anyone with the link — no account needed | ❌ No | Can be disabled at tenant or site level. Can set expiry (max days) and restrict to view-only |
| People in your organisation | Any authenticated user inside the organisation with the link | ✅ Yes (internal) | Cannot be shared externally. Good default for internal sharing |
| Specific people | Only the named individuals the sharer specifies (internal or external) | ✅ Yes | Most controlled link type. Creates targeted access for named users only |
| Existing access | Only for people who already have direct access to the item. Does not grant new access | ✅ Yes | No new permissions granted — purely a convenient link for existing collaborators |
⚙️ Sharing Policy Configuration
| Setting | What It Controls |
|---|---|
| External sharing — SharePoint | The tenant-wide maximum sharing level for all SharePoint sites. This is the primary external sharing dial |
| External sharing — OneDrive | The maximum sharing level for all users’ OneDrive. Must be equal to or more restrictive than the SharePoint tenant level |
| Limit external sharing by domain | Allow sharing only to specified domains, OR block sharing to specified domains. Mutually exclusive — allow list OR block list |
| Guests must sign in using the same account invitations were sent to | Prevents a guest from using a different email address to redeem the invitation |
| Allow guests to share items they don’t own | Controls whether external users can reshare items shared with them. Default: Off. Turn off to prevent cascade sharing |
| Anyone link settings — Maximum link expiration | Set a maximum number of days Anyone links can exist before automatically expiring (e.g., 30 days). 0 = no expiry |
| Anyone link settings — Link permissions | Restrict Anyone links to View only (no editing by anonymous users) |
| Default link type | What link type is pre-selected when a user opens the Share dialog — Anyone, People in your org, or Specific people |
Connect-SPOService -Url https://your-tenant-admin.sharepoint.com # Get current tenant-wide sharing settings Get-SPOTenant | Select-Object SharingCapability,OneDriveSharingCapability,RequireAcceptingAccountMatchInvitedAccount # Set tenant sharing to 'New and existing guests' only (recommended baseline) Set-SPOTenant -SharingCapability ExternalUserSharingOnly # Require Anyone links to expire after 14 days maximum Set-SPOTenant -RequireAnonymousLinksExpireInDays 14 # Set a specific site to internal-only sharing (most restrictive) Set-SPOSite -Identity https://your-tenant.sharepoint.com/sites/HRSite -SharingCapability Disabled # Audit all sites to see their sharing levels Get-SPOSite -Limit All | Select-Object Title,Url,SharingCapability | Sort-Object SharingCapability
💡 Best Practices
- Set the tenant default sharing level to “New and existing guests” or “Existing guests only” — avoid “Anyone” at tenant level unless there is a specific business requirement
- Configure Anyone link expiry (14–30 days max) and restrict Anyone links to view-only — this limits the exposure window and prevents anonymous users from editing corporate documents
- Set high-sensitivity sites (HR, Finance, Legal, Executive) to “Only people in your organisation” individually in site sharing settings
- Prevent guests from resharing (Allow guests to share items they don’t own: Off) — this stops the cascade where Guest A shares content to Guest B who shares to Guest C without admin visibility
- Configure domain restrictions (allow list for known partner domains) when your organisation only legitimately shares with specific companies
🎓 Interview Q&A
A user shares a document via an “Anyone” link with a partner. The partner forwards the email to a third party who opens the document. The SharePoint admin reviews the audit log but sees no entry for the third party’s access. Why?
An organisation’s SharePoint tenant sharing is set to “Only people in your organisation.” A site owner wants to share a document with a contractor who has a personal Gmail account. What happens?
An organisation allows external sharing at the tenant level but wants to ensure that the HR site never shares content externally. What is the correct configuration?
A user shares a file using a “People in your organisation” link and the recipient forwards the email to an external partner. Can the external partner open the file?
An organisation wants to prevent users from sharing SharePoint content to @competitor.com email addresses. What configuration achieves this?