Collaboration Technology Support Center - Microsoft - Collaboration Brief February 2007 Single Sign-On to a Microsoft Exchange Cluster Summary Users of the SAP NetWeaver Portal can take advantage of Single Sign-On to Web based Microsoft backend systems such as Outlook Web Access using SAP s SSO22KerbMap Module. In a high availability environment one method for increasing availability for Exchange mailbox servers is to use an Exchange cluster. Since the SSO22KerbMap Module must be installed on the backend Exchange servers this whitepaper describes the configuration steps that are necessary to implement the SSO22KerbMap Module in an Exchange cluster. Applies to SAP NetWeaver Portal 6.0 SP9 or higher Microsoft Active Directory 2003 (forest functional level set to Windows Server 2003) Microsoft Exchange 2003 two-node cluster (active/passive) SSO22KerbMap Module Contact For feedback or questions you can contact the Collaboration Technology Support Center via the.net Technologies forum in the.net interoperability area of SDN. Please check the.net interoperability area in SDN for any updates or further information. Authors Bio André Fischer works at SAP AG in the Strategic Alliance Microsoft Team. He is also a member of the Collaboration Technology Support Center Microsoft (CTSC MS) that addresses various kinds of interoperability topics regarding SAP and Microsoft solutions. Before joining SAP three years ago, André has lent his talents as an SAP technology consultant for more than eight years, and has gained significant experience in both the SAP and the Microsoft solution stack. In the last two years, André has also specialized in single sign-on, SAP active directory integration, SAP Exchange Infrastructure BizTalk integration and knowledge management Microsoft Windows integration. Torsten Laier works at REALTECH AG in the IT Services Team for 6 years. He is responsible for the implementation and running of the Microsoft Active Directory Services, Microsoft Exchange 2003 Servers and Microsoft Cluster Servers. Single Sign-On to Exchange Server 2003 in a Cluster 1 of 11
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Contents Introduction...4 The SSO22KerbMap Module...4 Integration scenario...4 How to Guide section...5 Step 1: Downloading the installation files... 5 Step 2: Installing the SSO22KerbMap Module on Each Node... 5 Copying the required files for the ISAPI filter to the local directories... 5 Determine the SPN used for constrained delegation... 6 Adapt the configuration file SSO22KerbMap.ini... 6 Configure the ISAPI Filter in the Internet Information Services Manager... 6 Step 3: Configure constrained delegation for each cluster node in Active Directory... 7 Step 3: Activation of the ISAPI Filter... 8 Result...9 Important Note...9 Conclusion...10 References...11 Single Sign-On to Exchange Server 2003 in a Cluster 3 of 11
Introduction The SSO22KerbMap Module is frequently used for the integration of Microsoft Exchange Server into a SAP NetWeaver Portal environment. As availability requirements for email have increased over the years so too did the need to guarantee Exchange availability. While front end servers can easily achieve high availability using a scale out strategy backend servers are single points of failure if no additional measures are taken to increase their availability. To achieve High Availability with Exchange Server it is therefore a common approach that customers decide to use clustering for their Exchange servers that are hosting the mailboxes. Using a Windows cluster with Exchange provides redundant servers so that if a node or a service on a node fails, the other node can assume the Exchange services. Since the SSO22KerbMap Module must be installed on each backend Exchange server that host mailboxes (see SAP Note 785343) this whitepaper describes the configuration steps that are necessary to implement the SSO22KerbMap Module in a Exchange cluster. The SSO22KerbMap Module A detailed description of the SSO22KerbMap Module can be found in the collaboration brief Using SAP Logon Tickets for SSO to Microsoft-based Web Applications. The ticket bridging mechanism leverages an enhancement of the implementation of the Kerberos protocol that has been introduced by Microsoft with Active Directory 2003. Using constrained delegation a service may request a (constrained) Kerberos ticket on behalf of a user for specified services only. Using protocol transition it is possible that the client may be authenticated using other methods than Kerberos. Based on this technology SAP has developed an ISAPI Filter called SSO22KerbMap Module. As described in SAP Note the SSO22KerbMap module has to be installed on the Exchange backend server, as the integrated Windows authentication is not supported for an Exchange front end server. Integration scenario REALTECH AG is using SAP NetWeaver Portal as their corporate portal. The portal can be accessed through the internet. Users can access their email through an integration of Outlook web access. In this extranet scenario, the SSO22KerbMap ISAPI module is used to acquire a Kerberos Ticket on behalf of the SAP Enterprise Portal user that is authenticated by the SAP Logon Ticket. REALTECH uses clustered Exchange servers to optimize the availability of their Exchange infrastructure. The clustered Exchange server can be accessed using the virtual server WDF-MX06. The active/passive two node cluster consists out of two physical nodes (WDF-EX03 and WDF-EX04). Single Sign-On to a Microsoft Exchange Cluster 4 of 11
How to Guide section The following How-To Guide section describes the steps necessary to configure the SSO22KerbMap module in an Exchange Cluster. The configuration steps can be summarized as follows: The SSO22KerbMap Module has to be installed in the Exchange virtual server on each cluster node. In contrast to a single server installation changes to the configuration have to be activated by moving the Exchange resources rather than using iisreset. Step 1: Downloading the installation files 1. Download the most recent version of the SSSO22KerbMap Module from SAP Service Marketplace at: http://service.sap.com/patches -> SAP Support Packages and Patches -> Entry by Application Group -> Additional Components -> SAPSSOEXT -> SAPSSOEXT -> Windows Server on <Platform> -> SSO22Kerbmap_<PL>.SAR 2. Download the most recent version of the SAP Logon Ticket Toolkit (SAPSSOEXT) from SAP Service Marketplace at: http://service.sap.com/patches -> SAP Support Packages and Patches -> Entry by Application Group -> Additional Components -> SAPSSOEXT -> SAPSSOEXT. 3. Download the most recent version of SAPSECULIB from SAP Service Marketplace at: http://service.sap.com/patches -> SAP Support Packages and Patches -> Entry by Application Group -> Additional Components -> SAPSECULIB. 4. Download the verify.pse file from the SAP Enterprise Portal at System Administration System Configuration Keystore Administration. Step 2: Installing the SSO22KerbMap Module on Each Node Step 2 includes the following tasks: 1. Copying the required files for the ISAPI filter to the local directories 2. Determine the SPN used for constrained delegation. 3. Adapt the configuration file SSO22KerbMap.ini 4. Configure the ISAPI Filter in the Internet Information Services Manager Copying the required files for the ISAPI filter to the local directories The following files that have been downloaded in step 1: SSO22KerbMap.dll SSO22KerbMap.pdb msvcr71.dll msvcp71.dll SSO22KerbMap.ini sapssoext.dll verify.pse are copied to the local directory C:\SSO22KerbMap on each cluster node. Single Sign-On to Exchange Server 2003 in a Cluster 5 of 11
Determine the SPN used for constrained delegation. 1. Log on as a domain administrator. 2. Use the command-line tool setspn.exe to list the configured Service Principal Names (SPN) for HOST for the LocalSystem account for each cluster node (here: WDF-EX03 and WDF-EX04). The Setspn.exe tool is included with the Microsoft Windows Server 2003 Support Tools. To install the Windows Support Tools, doubleclick Suptools.msi in the Support\Tools folder on the Windows Server 2003 CD. Comment [TL1]: Can be find in Microsoft Support-Tools setspn L WDF-EX03 Registered ServicePrincipalNames for CN=WDF- EX03,CN=Computers,DC=de,DC=realTech,DC=net: SMTPSVC/wdf-ex03.de.realtech.net SMTPSVC/WDF-EX03 HOST/WDF-EX03 HOST/wdf-ex03.de.realTech.net Adapt the configuration file SSO22KerbMap.ini The configuration file SSO22KerbMap.ini has to be adapted separately on each cluster node. On the first cluster node WDF-EX03 the configuration file SSO22KerbMap.ini contains the following entries: PseFile = C:\SSO22KerbMap\verify.pse LogLevel = 1 ServicePrincipalName = HOST/wdf-ex03.de.realTech.net FilterPriority = High SSO2AccountAttribute = userprincipalname On the second cluster node WDF-EX04 the configuration file SSO22KerbMap.ini contains the following entries: PseFile = C:\SSO22KerbMap\verify.pse LogLevel = 1 ServicePrincipalName = HOST/wdf-ex04.de.realTech.net FilterPriority = High SSO2AccountAttribute = userprincipalname Configure the ISAPI Filter in the Internet Information Services Manager Install the SSO22KerbMap Mapping Filter that means the SSO22KerbMap.dll as an ISAPI filter on the website the target application is running on, as follows: Single Sign-On to a Microsoft Exchange Cluster 6 of 11
Step 3: Configure constrained delegation for each cluster node in Active Directory Constrained delegation has to be configured for each cluster node separately. To do this the Trusted-to-Authenticate-for-Delegation flag has to be configured for both cluster nodes separately. In the following we describe the configuration steps for cluster node 1 (WDF-EX03): 1. Open the MMC Active directory Users and Computers. 2. Choose <Your Windows_2003_domain> and locate the computer account of the cluster node (here WDF-EX03). 3. Right-click the cluster node and choose Properties. 4. Select Delegation and Trust this computer for delegation to specified services Single Sign-On to Exchange Server 2003 in a Cluster 7 of 11
5. only. 6. Select Use any authentication protocol and choose Add. 7. Select Users or Computers and enter the cluster node that has been selected above as object name (here WDF-EX03). 8. Choose Check Names and OK. 9. Add the SPN for the HOST service type for your cluster node which 10. was determined in Step 2 Steps 1 to 10 have to be repeated with the node WDF-EX04. Replace the hostname WDF-EX03 with WDF-EX03 in the configuration steps described above. Step 3: Activation of the ISAPI Filter After the changes have been done one has to move the resources from the active node to the inactive node. In a clustered environment moving the resources will have a minimal impact on the users currently using the Exchange environments. Single Sign-On to a Microsoft Exchange Cluster 8 of 11
Result The following screenshot shows the integration of Outlook Web Access in REALTECH s corporate portal: Important Note Please check SAP Note 735639 SSO22KerbMap: Known issues before installing the SSO22KerbMap Module. At the time of writing of this whitepaper for each backend server that uses the SSO22KerbMap Module, the Microsoft Hotfix 907524 has to be installed to avoid a memory leak in Windows 2003 caused by Microsoft s lsass.exe. Single Sign-On to Exchange Server 2003 in a Cluster 9 of 11
Conclusion The SSO22KerbMap Module has to be installed in the Exchange virtual server on each cluster node. The setup of the SSO22KerbMap Module on a node of an Exchange Cluster is very similar to the setup for a single server. In contrast to a single server installation changes to the configuration have to be activated by moving the Exchange resources rather than using iisreset. Since the Exchange resources have to be moved between the cluster nodes in order to activate the changes the planning for a minimal downtime may have to be taken into account. Single Sign-On to a Microsoft Exchange Cluster 10 of 11
References Note 735639 - SSO22KerbMap: Known issues https://service.sap.com/sap/support/notes/735639 Note 785343 - SSO22KerbMap: Configuration for SSO for Outlook Web Access https://service.sap.com/sap/support/notes/785343 Step-by-Step Guide: SSO22KerbMap ISAPI Module Collaboration Brief Using SAP Logon Tickets for Single Sign on to Microsoft based web applications https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/47d0cd90-0201- 0010-4c86-f81b1c812e50 A memory leak occurs in the Lsass.exe process after you configure constrained delegation in Windows Server 2003 http://support.microsoft.com/default.aspx?scid=kb;en-us;907524 Single Sign-On to Exchange Server 2003 in a Cluster 11 of 11