Applies to: Exchange Server 2013

Topic Last Modified: 2012-11-21

Information workers frequently need to collaborate with partners, customers, vendors, or other contacts outside their Exchange organization. For effective cross-organization collaboration, your users may need to share their free/busy (also known as calendar availability) information for scheduling meetings or, depending on the nature of the business relationship, share more detailed calendar information. Similarly, users may also need to share their contacts with these external recipients. In Microsoft Exchange Server 2013, federated sharing allows you to accomplish all of these goals.

Contents

Collaboration before Exchange 2013 and federated sharing

Federated sharing

Firewall considerations for federated sharing

Coexistence with Exchange 2010

Coexistence with Exchange 2007

Sharing documentation

Collaboration before Exchange 2013 and federated sharing

Earlier versions of Exchange had limited sharing capabilities and required complex set up and ongoing maintenance. For example, to share availability information with users in another Exchange organization, you had to use the Inter-Organization Replication tool to replicate public folders between Exchange organizations. This process required you to create Active Directory trusts between both organizations, as well as manage service account credentials.

For recipients to be visible in Exchange address lists, many organizations used different tools such as GALSync to synchronize one organization's recipients to another organization. Setting up trusts, managing credentials, and replication with multiple external organizations was difficult and cumbersome. Creating Active Directory forest or domain trusts and credential management also had security implications. Opening additional ports on firewalls between the two organizations or establishing a virtual private network (VPN) was also required.

With the introduction of Exchange Web Services, the Availability service, and the Client Access server role in Exchange Server 2007, the replication of public folder free/busy data wasn't necessary. However, trust or credential information and global address list (GAL) synchronization was still necessary to make free/busy information available to external organizations.

Sharing a Calendar or Contacts folder also involved assigning permissions to access the folder to users in trusted organizations. The only way to accomplish this was by creating Active Directory trusts between the two organizations, which had additional security implications.

In Exchange 2010, federated sharing (also known as federated delegation) became even easier. The New Federation Trust and Manage Federation wizards allowed administrators to quickly create a federation trust with the Microsoft Federation gateway and easily create and configure organization relationships with other federated Exchange organizations. Sharing policies also enabled the flexibility for individual Exchange users to share their calendar availability and contacts information on an individual-to-individual basis with either anonymous or other Exchange-based external recipients.

For more information, see How to Configure the Availability Service for Cross-Forest Topologies.

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Federated sharing

Using federated sharing in Exchange 2013, users can share information with recipients in external federated organizations by establishing a federation trust with the Microsoft Federation Gateway and creating organization relationships between Exchange 2013 organizations. Sharing information between Exchange 2013 and Exchange 2010 SP2 or later organizations is also supported. Exchange 2013 organizations can also use sharing policies to allow users to create individual sharing relationships with recipients in other organizations. Federated sharing uses the Microsoft Federation Gateway, a free cloud-based service, as the trust broker between two federated organizations. To enable federated sharing, each organization wishing to share information must establish a one-time federation trust with the Microsoft Federation Gateway and configure either an organization relationship or sharing policies with each other.

Important:
If you disable the federated organization identifier for your Exchange organization, all federation sharing features are disabled for your organization.

To learn more about the Microsoft Federation Gateway and federation trusts, see the following topics:

Federated sharing offers two ways for users to share calendar and contact information with external recipients: Organization relationships and sharing policies.

Organization relationships

Organization relationships allow you to enable federated sharing with another federated Exchange organization for the purpose of sharing calendar free/busy information between users in both organizations. Organization relationships are one-to-one relationships between two Exchange organizations, not a relationship between individual users in the Exchange organizations. Rather than requiring a complex Active Directory forest or domain trust configuration between the two organizations (which may also require opening multiple ports on firewalls in both organizations or establishment of a VPN), both organizations are required only to establish a single federation trust with the Microsoft Federation Gateway and to configure their federated organization identifier prior to configuring the organization relationship with each other.

Requirements for organization relationships

The following are required for organization relationships:

  • An Exchange 2013 Client Access server exists in each Exchange organization. An Exchange 2013 organization can also establish an organization relationship with Exchange 2010 organizations as long as the Exchange 2010 organization has Client Access servers that have Service Pack 2 (SP2) or higher installed.

  • Each Exchange organization has created a federation trust with the Microsoft Federation Gateway.

  • Each Exchange organization has configured a federated organization identifier. Domains used for generating users' e-mail addresses have been added to the organization identifiers.

  • An organization relationship exists in each corresponding organization.

Note:
We highly recommend that users in both federated Exchange organizations use Outlook 2010 or later versions when using federated sharing features. Pre-Outlook 2010 client users can't specify SMTP addresses of external recipients to display availability information. Recipients must be picked from the GAL, which requires GAL synchronization with the external organization.

Creating organization relationships

When you create an organization relationship with an external federated Exchange organization, users in the external organization can access your users' calendar free/busy information. No replication of GAL information is required. With this configuration in place, Outlook 2010 and Office Outlook Web App users can simply enter the SMTP address of an external recipient when scheduling meetings.

When creating an organization relationship, you can specify one of the following three levels of calendar availability access:

  • No free/busy access

  • Free/busy access with time only

  • Free/busy access with time, plus subject and location

For users in your organization to have access to external users' free/busy information or to allow for one-way sharing of their free/busy information with the external organization, the administrator in the external organization must also create an organization relationship with your organization. However, the external administrator can specify a different level of access for their users that's different from the level you specified. In a one-way sharing example, the external administrator would configure their organization relationship so that their users' free/busy information isn't shared with users in your organization, but the free/busy information for your users would be visible to the users in the external organization based on your organization relationship settings.

Note:
If users don't want to share their free/busy information with others, they can modify the Default permission entry in Outlook. To do this, users navigate to the Calendar Properties > Permissions tab, select the Default permission, and select None from the Permission Level list. Their free/busy information won't be visible to internal or external users, even if an organization relationship exists with an external organization. The organization relationship always honors the permissions set by the user.

When you create an organization relationship, Exchange 2013 Client Access servers connect to the Autodiscover Web service published by the external organization to obtain the Availability service endpoint. You can also specify the external organization's Availability service endpoint manually when creating the relationship.

To create an organization relationship with an external organization, you can use the New organization relationship wizard in the Exchange Administration Center (EAC) or the New-OrganizationRelationship cmdlet in the Exchange Management Shell.

For details instructions about how to create an organization relationship, see Create an Organization Relationship.

Sharing policies

Unlike organization relationships, which only enable sharing of free/busy information with recipients in other federated Exchange organizations, sharing policies enable individual, user-established, people-to-people sharing of both calendar and contact information with different types of external users. Sharing polices allow your users to share both their free/busy and contact information (including the Calendar and Contacts folders) with recipients in other external federated Exchange organizations. For recipients that aren't in an external federated organization or are in non-Exchange organizations, sharing policies allow people-to-people sharing of their calendar information with anonymous users through the use of Internet Calendar Publishing.

With sharing policies, you won't need to manage your users' collaboration relationships. Instead, they get to decide which external recipients they want to collaborate with. Using Outlook 2010 or Outlook Web App, users can invite external recipients in other federated domains to access their Calendar or Contacts folder and also request that they share theirs in return. Users can also grant anonymous access to their calendar information to any individual who has Internet access. With sharing policies, you only control what types of users they can share information with and how much information they can share. If necessary, you can also disable a user's or group's sharing policy.

Sharing policies are assigned to mailbox users. The default sharing policy applied to users allows availability information to be shared with all external federated domains. After you create a federation trust with the Microsoft Federation Gateway and configure the federated organization identifier, users can invite users in any external federated organization to share their calendar and contact information.

Important:
To participate in federated sharing, the external user's organization must also have a federation trust established with the Microsoft Federation Gateway, and the federated organization identifier must be configured.

To allow access to user's calendars by recipients in non-federated domain organizations, such as family members, friends, or users in non-Exchange organizations, a separate sharing policy should be created that allows for anonymous calendar access through the use of Internet Calendar Publishing. For details, see Create a Sharing Policy.

Sharing policies can contain pairs of domain names and the sharing actions allowed for users from those domains. You can specify the following actions that apply to the external domain specified in a sharing policy:

  • Calendar sharing with free/busy information only

  • Calendar sharing with free/busy information, plus subject and location

  • Calendar sharing with free/busy information plus subject, location and body

  • Contacts sharing

  • Calendar sharing with free/busy information only, Contacts sharing

  • Calendar sharing with free/busy information, plus subject and location, Contacts sharing

  • Calendar sharing with free/busy information plus subject, location, and body, Contacts sharing

When creating a sharing invitation, your users can select the information they want to share, provided that the action is allowed by the user's sharing policy. For example, let's say you create a sharing policy with the following settings for Fabrikam and other federated domain organizations:

  • Calendar sharing with free/busy information, plus subject and location for external users in Fabrikam.com

  • Calendar sharing with free/busy information only for external users in all other federated domain organizations (represented by the asterisk [*] symbol)

Users who have this policy applied can either share their calendar free/busy information with other federated domain organizations or can also share additional limited details if they invite users from Fabrikam.com.

For details about how to create a sharing policy, see Create a Sharing Policy.

For details about how to apply a sharing policy to users, see Mailbox Features.

Requirements for federated sharing policies

The following are required for sharing policies between federated domain organizations:

  • An Exchange 2013 Client Access server exists in each Exchange organization. An Exchange 2013 organization can also establish an organization relationship with Exchange 2010 organizations as long as the Exchange 2010 organization has Client Access servers that have Service Pack 2 (SP2) or higher installed.

  • Each Exchange organization has created a federation trust with the Microsoft Federation Gateway.

  • Each Exchange organization has configured a federated organization identifier. Domains used for generating users' e-mail addresses have been added to the organization identifiers.

  • User mailboxes are located on Exchange 2013 or Exchange 2010 Mailbox servers in each Exchange organization.

  • Only Outlook 2010 and Outlook Web App users can create sharing invitations.

Requirements for non-federated sharing policies

The following are required for sharing policies with non-federated domain organizations or individual anonymous access:

  • An Exchange 2013 Client Access server exists in the Exchange organization that's sharing user's calendar information.

  • User mailboxes are located on Exchange 2013 Mailbox servers in the Exchange organization that's sharing user's calendar information.

  • The Client Access server must be enabled for Outlook Web App access.

Comparing organization relationships and sharing policies

Although organization relationships and sharing policies both allow sharing of free/busy information with external users, they're intended for different scenarios. Organization relationships are created to collaborate with external federated organizations on an organization-to-organization level and are limited to sharing only free/busy information. Sharing policies govern what calendar and contact information your individual users can share with other individual users in external federated organizations, non-federated Exchange organizations, non-Exchange organizations, and anonymous users.

The following table lists the differences between organization relationships and sharing policies.

Organization relationships vs. sharing policies

Functionality Organization relationship Sharing policy

Requires a federation trust for your organization

Yes

Yes when sharing with other federated domain organizations. Not required for Internet sharing policies.

Recommends that the external domain be federated

Yes

Yes when sharing with other federated domain organizations. Not required for Internet sharing policies.

Allows sharing of free/busy information (including subject and location) with external organizations for a set of many users.

Yes

No

Allows sharing of Calendar folders with free/busy information

No

Yes

Allows sharing of Calendar folders with free/busy information, including subject and body

No

Yes

Allows sharing of contacts

No

Yes when sharing with other federated domain organizations. Not required for Internet sharing policies.

Requires users to send a sharing invitation to external recipients

No

Yes

Provides an access method

Your Client Access server accesses the Client Access server of the external organization and retrieves free/busy information for the external user when requested.

Your Client Access server accesses the Client Access server of the external organization and subscribes to the external user's Calendar or Contacts folder for federated domain organizations. For Internet sharing policies, external users access either a restricted or public URL on the Client Access server.

Can be applied to all external domains

No (a one-to-one relationship between two Exchange 2013 organizations)

Yes

Provides users with different sharing experiences with external recipients

No

Yes, based on the sharing policy that's applied

Disables sharing for some users

Yes, by specifying a security distribution group for the organization relationship

Yes, by disabling the sharing policy that's applied

Requires that the mailbox reside on an Exchange 2013 Mailbox server

No

Yes

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Limitations of free/busy sharing

The following limitations apply when sharing free/busy information between federated Exchange organizations:

  1. Outlook Web Access 2003   When a user in an Exchange 2003 organization uses Outlook Web Access to access free/busy for users in a remote Exchange 2013 organization, the request will fail. Outlook Web Access connections from Exchange 2003 can’t make WebDAV (Web-based Distributed Authoring and Versioning) connections to a free/busy system folder to retrieve the free/busy information for remote users. Because Exchange 2013 doesn’t support WebDAV connections, the Exchange 2003 server can't connect to External (FYDIBOHF25SPDLT) on the Exchange 2013 CAS server for Outlook Web Access requests. Outlook clients don’t experience this limitation because they use MAPI instead of WebDAV when connecting to External (FYDIBOHF25SPDLT).

  2. Wide Area Network (WAN) latency   In Exchange 2003 organizations, the replicas for all free/busy folders must reside on Exchange 2010 SP2 Mailbox servers. In environments where Exchange 2003 public folder databases are located in multiple physical sites, there may be excessive latency and performance issues if internal free/busy queries have to traverse WAN links to access Exchange 2010 public folder databases not located in the same physical site.

  3. Free/busy information period   Free/busy information requests to an Exchange 2007 organization from an Exchange 2013 organization may fail due to a mismatch in the requested free/busy information period. By default, Exchange 2007 accepts availability requests for 42 days of free/busy information and Exchange 2013 may request 62 days of free/busy information. If the request exceeds the default 42 limit imposed by Exchange 2007, the request will fail.

    Follow the steps below to configure your Exchange 2007 CAS servers to accept longer period free/busy information requests:

    1. On all your Exchange 2007 CAS servers, open the following file with a text editor such as Notepad: <Exchange Installation Path>\V14\ClientAccess\ExchWeb\EWS\web.config

      Caution:
      Before you make any changes to the web.config file, make a copy of the file and store it in a safe location.
    2. Locate the appSettings section in the web.config file.

    3. Add a new key “<add key="maximumQueryIntervalDays" value="62" />” and save the web.config file.

      Note:
      The maximumQueryIntervalDays value isn’t present by default. When this value isn’t present, Exchange 2007 uses the default interval of 42 days.
    4. Stop and restart the Microsoft Internet Information Services (IIS) on all the Exchange 2007 CAS servers.

  4. Exchange organizations that have both on-premises and cloud users   If you configure federated sharing with another Exchange organization that is configured in a hybrid deployment with Microsoft Office 365, free/busy availability lookups for Office 365-based or remote users that have been moved to the cloud will fail. Because the organization relationship for your Exchange organization is with the remote on-premises Exchange organization, not the Office 365-based Exchange Online organization, the free/busy request can’t query the Office 365-based users. Exchange 2013 doesn’t support functionality to proxy these availability requests through the on-premises organization to the Office 365 service.

For details about how to configure free/busy sharing between common Exchange deployments, see Configuring Federated Sharing Between Exchange Organizations.

Firewall considerations for federated sharing

Federated sharing features require that the Client Access servers in your organization have outbound access to the Internet by using HTTPS. You must allow outbound HTTPS access (port 443 for TCP) to all Exchange 2013 Client Access servers in the organization.

For an external organization to access your organization's free/busy information, you must publish at least one Client Access server to the Internet. This requires inbound HTTPS access from the Internet to the Client Access server. Client Access servers in Active Directory sites that don't have a Client Access server published to the Internet can use Client Access servers in other Active Directory sites that are accessible from the Internet. The Client Access servers that aren't published to the Internet must have the external URL of the Web services virtual directory set with the URL that's visible to external organizations.

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Coexistence with Exchange 2010

In organizations that contain both Exchange 2010 and Exchange 2013 servers, users who have a mailbox on an Exchange 2010 Mailbox server can use organization relationships to share free/busy information with recipients in external Exchange 2013 federated domain organizations. The Exchange 2010 Client Access and Mailbox servers must be running SP2 or later, and you must have at least one Exchange 2013 Client Access server in the Exchange 2010 organization.

Coexistence with Exchange 2007

In organizations that contain both Exchange 2013 and Exchange 2007 servers, users who have a mailbox on an Exchange 2007 Mailbox server can use organization relationships to share free/busy information with recipients in external federated domain organizations. The Mailbox server must be running Exchange 2007 SP2 or later, and you must have at least one Exchange 2013 Client Access server in the Exchange organization. You can use organization relationships by introducing a single Exchange 2013 Client Access server in the organization, providing a more robust solution than solutions that synchronize free/busy information and require GAL synchronization.

When using Outlook 2010 or Outlook Web App to scheduling a meeting on an Exchange 2007 server, a user who has a mailbox on an Exchange 2007 server can see free/busy information for a user in the external organization. Free/busy information for Exchange 2007 mailboxes is visible to recipients in the external organization.

Sharing policies are assigned to Exchange 2013 mailbox users. To use sharing policies, a mailbox must be located on an Exchange 2013 Mailbox server. Only Outlook 2010 and Outlook Web App clients can be used to generate or respond to sharing invitations.

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Sharing documentation

The following table contains links to topics that will help you learn about and manage sharing in Exchange 2013.

Topic Description

Federation

Learn more about the underlying trust infrastructure that supports federated sharing, an easy method for users to share calendar and contact information with recipients in other external federated organizations.

Organization Relationships

Learn more about the one-to-one relationships between federated Exchange organizations that enable calendar free/busy sharing.

Sharing Policies

Learn more about the person-to-person policies that enable calendar and contact folder sharing.