Applies to: Exchange Server 2010 SP1

Topic Last Modified: 2012-07-23

Estimated time to complete: 5 minutes

To enable Outlook 2010, Outlook 2007, and mobile clients to connect to mailboxes in the cloud-based organization, and to support the configuration of organization relationships between the on-premises and cloud-based organizations, you need to configure two Autodiscover DNS records. Autodiscover automatically configures client settings so that users don't need to know server names or other technical details to configure their mail profiles. It also enables organization relationships to retrieve information required to automatically establish communication between the on-premises and cloud-based organizations to support hybrid deployment features such as free/busy sharing.

This topic is meant to be read as part of the Microsoft Exchange Server 2003 and Office 365 Hybrid Deployment checklist. Information or procedures in this topic may depend on prerequisites configured in topics earlier in the checklist. To view the checklist, see Checklist - Exchange 2003 and Office 365 Hybrid Deployment.

How do I do this?

You need to configure the following DNS records to enable Autodiscover lookups for the on-premises and cloud-based organizations:

  • On-premises   The Autodiscover DNS record for your on-premises organization needs to refer requests for to your on-premises hybrid server. You can use either a CNAME DNS record or an A DNS record. A CNAME DNS record must refer to the FQDN of your on-premises hybrid server. An A DNS record must point to the external IP address of the hybrid server or your firewall depending on your network configuration.

    If you have an existing Autodiscover record configured for your on-premises organization, you must configure it to point to your on-premises hybrid server. If this Autodiscover record doesn't point to an on-premises server running Exchange 2010 SP1 or greater, some hybrid deployment features won't work.
  • Cloud-based   The Autodiscover DNS record for your cloud-based organization needs to refer requests for to the FQDN of the Autodiscover service for the cloud-based organization. This needs to be a CNAME DNS record and its target needs to be

This table shows examples of the DNS records that you need to configure.

Autodiscover record DNS record type Target


If using CNAME DNS:

If using A DNS:  External IP address of your hybrid server or firewall


Refer to your DNS host's Help for more information about how to add a CNAME record to your DNS zone.

How do I know this worked?

To verify that you've configured the Autodiscover DNS record for the cloud-based organization correctly, do the following on an Internet-accessible computer that can perform DNS lookups.

  1. Open a Windows command prompt.

  2. Run the following command.

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The following should be returned if you've correctly configured the DNS record. (Depending on your DNS configuration, it may take an hour or more for changes to DNS to replicate across the Internet.) The IP address returned may be different than the address in the example below.

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Non-authoritative answer:

Repeat the nslookup command using the Autodiscover DNS record for your on-premises organization. For example, Verify that the output of the nslookup command matches the FQDN or IP address of your on-premises hybrid server.

Having problems? Ask for help in the Office 365 forums. To access the forums, you'll need to sign in using an account that's granted administrator access to your cloud-based service. Visit the forums at: Office 365 Forums