Our next step also has me hmmmmming.

In the case of SBS 2008 migration to Essentials more than likely we started with one IP and we’re going to end with one IP.    So we will have our old Exchange and our new Exchange connecting back in on the same static public IP probably using ARR routing tables at some point in time.

This legacy host name it done up on the DNS provider, so whomever is in control of your server domain name, you’ll put this legacy host name setting up there.

For example godaddy’s dns.

 You would add it in the A record section up in their DNS manager

So in there you’d click on quick add and you’d add a legacy host name up there in addition to the normal alias you’d use for email.

Create legacy Exchange host name

Estimated time to complete: 5 minutes

You need to create a legacy domain name system (DNS) host name so your legacy Exchange 2007 environment and Exchange 2013 can coexist. For example, if your domain name is currently contoso.com, you’re likely using a host name of mail.contoso.com or www.contoso.com for external client access to Exchange. During coexistence, we recommend creating and using, for example, a host name of legacy.contoso.com. You’ll associate the legacy host name with your existing Exchange 2007 server and associate your current host name (for example, mail.contoso.com) with your Exchange 2013 Client Access server. Your end users will not see or use the legacy host name. It will be used by Autodiscover and Client Access servers when redirecting legacy users to a legacy server.

All client connections will be redirected, including Exchange ActiveSync, Outlook Web App, POP3, and IMAP4. After the legacy host name has been configured, users will be able to access their mailbox regardless of whether it’s on Exchange 2007 or Exchange 2013. If you’re upgrading from Exchange 2007 to Exchange 2013, Availability service requests will also be redirected.

You need to create a public DNS record for the legacy.contoso.com host name to point to the external IP address of your Exchange 2007 server. The following is an example of the DNS record that you’d create with your public DNS provider, such as GoDaddy.

You might need to make changes to your firewall to support this new legacy host name. You might need to add new firewall rules, add an external IP address for your Exchange 2007 server, or make other configuration changes. If your organization has a network management group, a security review process, or change management process, you may need to request permission to perform these changes or have someone else make them for you.

Host name DNS record type Value



To verify that you’ve successfully configured your public DNS records, do the following:

  1. Open a command prompt and run nslookup.exe.
  2. Change to a DNS server that can query your public DNS zone.
  3. In nslookup, look up the record for the legacy.contoso.com host name you created. Verify that the IP address that’s returned matches the external IP address of your Exchange 2007 server.

Having problems? Ask for help in the Exchange forums. Visit the forums at: Exchange Server, Exchange Online, or Exchange Online Protection


One Response to SMBKitchen: Adding a legacy host name

  1. Joshua says:

    This is standard for any Exchange migration. The purpose is if you have not moved all the mailboxes to the new exchange yet, you should have everyone using OWA connect to the new server. The new server will determine if the mailbox is on the new server, or is still on the old server, and if on the old server will automatically redirect the client to the legacy domain name, which will connect to the old servers OWA.

    If you only have 1 external IP address, obviously you cannot set up port forwarding to go to 2 different devices for 1 IP/Port combination, so you will just need to do the migration as quickly as possible so that nobody gets left on the old server, and therefore no need for a legacy domain name.