Troubleshooting Exchange Server 2010 : Troubleshooting Client Connectivity (part 1) - Troubleshooting Autodiscover

Many of us subconsciously assume that "client" means Outlook, but it's not the only client software (or device) capable of accessing Exchange Server 2010. Outlook is the most popular, but there's also Outlook Web App and ActiveSync-enabled devices like Windows Mobile smartphones and Apple's iPhone. Despite the obvious differences between these devices, they all rely on the same basic mechanisms to connect—locating the Client Access server and connecting to the appropriate interface. They also depend on the health and proper configuration of network resources, including IP address schemes, site definitions, and DNS records and zones.

Before troubleshooting the server components, it's a good idea to test the following:

• Verify that the client can successfully ping the Client Access server by both IP and fully qualified domain name. If the forest includes multiple domains, ping the Client Access server by short (NetBIOS) name as well so that you can verify that NetBIOS names are being resolved correctly.

• For a mobile device, verify that the device can access Internet-based content by browsing to a known website.

• Verify the username and password combination for the mailbox you're attempting to access.

If these tests fail, the problem may not be unique to Exchange.

1. Troubleshooting Autodiscover

The most important initial consideration for Outlook client connectivity (specifically Outlook 2007 and the upcoming Outlook 2010) is the Autodiscover service.The Autodiscover service generates an XML file with all the appropriate user settings and sends it to Outlook, which then uses that information to connect the user to his or her mailbox. But how does Outlook even know where to find Autodiscover in the first place? Depending on the client's location (on the corporate network or the Internet), the client will either check Active Directory for an appropriate record or look for a specific URL. There are a few different ways to check this, all of them very useful.

1.1. Internal Clients

Internal clients connect to Active Directory and check for the service connection point (SCP) records, which are automatically published as part of the setup process. One easy way to validate Autodiscover for internal clients is with Outlook 2007 or 2010's Test E-mail AutoConfiguration option. This useful little feature was introduced in Outlook 2007 and simply goes through the steps for Autodiscover without making changes to current configuration. To access this wizard, simply start Outlook, Ctrl+right-click the Outlook icon in the notification area (system tray), and then select Test E-mail AutoConfiguration from the context menu. You can see a sample of the Test E-mail AutoConfiguration tool in Figure 1.

Figure 1. Using the Test E-mail AutoConfiguration tool

After providing appropriate user credentials and ensuring that only the check box for Use AutoDiscover is selected, click Test to begin the configuration check. The AutoConfiguration test checks for much more than just Autodiscover: it also locates Availability Service, OOF, Offline Address Book, Unified Messaging, Outlook Web App, and Exchange Control Panel URLs, making this one of the most useful client-based configuration tools.

If the AutoConfiguration test fails, the tool will display an error message. The four most common error codes, along with root causes, are listed in Table 1.

The AutoConfiguration test also works for external Outlook clients (including those connecting via Outlook Anywhere), so it's useful for the External Clients scenario listed next.

1.2. External Clients

If external clients can't connect to Exchange, you may need to ensure that you've configured your environment for external access for the appropriate clients. Hopefully you've already done this, but if you haven't, here's what you need to do for an organization named somorita.com:

• To configure the external Autodiscover name for Outlook Anywhere, the appropriate command is Enable-OutlookAnywhere -Server CAS01 -ExternalHostname "mail.somorita.com" -ExternalAuthenticationMethod "Basic" -SSLOffloading:$False.

• The equivalent command for Web Service clients is Set-WebServicesVirtualDirectory -identity "CAS01\EWS (Default Web Site)" -externalurl https://mail.somorita.com/EWS/Exchange.asmx -BasicAuthentication:$True. In each case you'll obviously need to substitute your own domain namespace.

• The equivalent command for ActiveSync clients is Set-ActiveSyncVirtualDirectory -identity "CAS01\Microsoft-Server-ActiveSync (Default Web Site)" -externalurl https://mail.somorita.com/Microsoft-Server-ActiveSync. In each case, you'll obviously need to substitute your own domain namespace.

• The equivalent command for the Offline Address Book is Set-OABVirtualDirectory -identity "CAS01\OAB (Default Web Site)" -externalurlhttps://mail.somorita.com/oab. In each case, you'll obviously need to substitute your own domain namespace.

The Test E-mail AutoConfiguration option in Outlook 2007 and 2010 works for external Autodiscover as well as internal, and because Autodiscover is a published web address, you can always test it with a web browser (by navigating to https://somorita.com/autodiscover/autodiscover.xml, or whatever address you published). For external clients, however, there's a much better solution available online. In 2008 Microsoft quietly released the beta of an extremely useful tool called the Exchange Server Remote Connectivity Analyzer (ExRCA for short), which simulates a number of connectivity scenarios, including Autodiscover, Exchange ActiveSync, Outlook Anywhere, and incoming Internet SMTP email. You can find this tool (shown in Figure 2) at www.testexchangeconnectivity.com.

Figure 2. The main page of the Remote Connectivity Analyzer web page

To use ExRCA, simply browse to www.testexchangeconnectivity.com and select the appropriate option (in this case we'll choose Exchange ActiveSync Autodiscover). Because you're providing information to a third party (in this case, Microsoft), it's a good idea to create a brand-new test user just for this purpose instead of exposing user credentials. Once you've provided the appropriate details, click OK to launch the test; the resulting output should either confirm that all is well or give you specific feedback on what might be missing. In Figure 3, ExRCA determined that the Autodiscover DNS name was not properly registered for the domain.