Fix: Access CNAME based URL from same server (SharePoint, CRM etc)

You may have observed you can’t access host header or cname FQDN URLs from same sharepoint & crm IIS Web Server. I grabbed these things from below MS KB Articles. For me the Method 1 always fix the issue which is recommended by MS.

Due to this URL access error, you may face issues with MS CRM Email Router. If you can’t access the CRM Applicatioin URL from same machine your email router will not able to crawl the users & may through an error.
http://support.microsoft.com/kb/896861/en-us

http://support.microsoft.com/kb/281308

Method 1: Specify host names (Preferred method if NTLM authentication is desired)

To specify the host names that are mapped to the loopback address and can connect to Web sites on your computer, follow these steps:

1. Click Start, click Run, type regedit, and then click OK.
   
2. In Registry Editor, locate and then click the following registry key:
   

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0
   

3. Right-click MSV1_0, point to New, and then click Multi-String Value.
   
4. Type BackConnectionHostNames, and then press ENTER.
   
5. Right-click BackConnectionHostNames, and then click Modify.
   
6. In the Value data box, type the host name or the host names for the sites that are on the local computer, and then click OK.
   
7. Quit Registry Editor, and then restart the IISAdmin service.
   

Method 2: Disable the loopback check (less-recommended method)

The second method is to disable the loopback check by setting the DisableLoopbackCheck registry key.

To set the DisableLoopbackCheck registry key, follow these steps:

1. Click Start, click Run, type regedit, and then click OK.
   
2. In Registry Editor, locate and then click the following registry key:
   

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
   

3. Right-click Lsa, point to New, and then click DWORD Value.
   
4. Type DisableLoopbackCheck, and then press ENTER.
   
5. Right-click DisableLoopbackCheck, and then click Modify.
   
6. In the Value data box, type 1, and then click OK.
   
7. Quit Registry Editor, and then restart your computer.
   

You may need to do (Mostly applies when we use Alias, CNAME records to access the server over network using UPN)

Step -1

1. Create the CNAME record for the file server on the appropriate DNS server, if the CNAME record is not already present.
   
2. Apply the following registry change to the file server. To do so, follow these steps:
   
   1. Start Registry Editor (Regedt32.exe).
      
   2. Locate and click the following key in the registry:
      

      HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters
      

   3. On the Edit menu, click Add Value, and then add the following registry value:
      

      Value name: DisableStrictNameChecking
      Data type: REG_DWORD
      Radix: Decimal
      Value: 1
      

   4. Quit Registry Editor.
      
3. Restart your computer.
   

Step-2

You may also have to set the SPN (Service Principal Name) for the Alias Name.

For example, you may have to enter a command that resembles the following commands:

setspn -a host/aliasname targetserver

setspn -a host/aliasname.contoso.com targetserver