Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine whether the networkAddress attribute contains the ncacn_ip_tcp string. The Exchange Server Analyzer displays an error if either of the following conditions exist:

In Microsoft Office Outlook® Web Access for Exchange Server 2003, the front-end server examines the networkaddress attribute value when it tries to connect to an Exchange back-end server.

Exchange 2000 Server does not do this with Outlook Web Access.

The front-end server requires a fully qualified domain name (FQDN) value. The front-end server checks for a period in the value that is returned for networkaddress ncacn_ip_tcp. The connection request for the mailbox on the specific back-end server fails and the front-end server returns an "HTTP 500 Internal Server Error" error message to the user if the following conditions exist:

You must update the networkaddress ncacn_ip_tcp value on the server object in Active Directory to ensure appropriate functionality of Outlook Web Access 2003. The affected server name is provided in the Exchange Server Analyzer error message.

If you incorrectly modify the attributes of Active Directory objects when you use Active Directory Service Interfaces (ADSI) Edit, the LDP (ldp.exe) tool, or another Lightweight Directory Access Protocol (LDAP) version 3 client, you may cause serious problems. These problems may require that you reinstall Microsoft Windows Server™ 2003, Exchange Server 2003, or both. Modify Active Directory object attributes at your own risk.
Before you update the ncacn_ip_tcp value, read the rest of this article. To minimize the downtime that is caused when you restart Exchange Server services, you should perform an additional procedure before you restart the Exchange Server services.
To update the ncacn_ip_tcp value on the networkAddress attribute
  1. Start the ADSI Edit tool from Windows 2000 Server support tools or from Windows Server 2003 support tools.

  2. Expand the following nodes:

    • Configuration Container

    • Configuration

    • Services

    • Microsoft Exchange

    • Organization_Name

    • Administrative Groups

    • Administrative_Group_Name

    • Servers

  3. Right-click Exchange_Server_Name, and then click Properties.

  4. Click networkaddress in the Attributes list, and then click Edit.

  5. Add a new value for ncacn_ip_tcp. Use the FQDN of the server instead of the NetBIOS name or the host name of the server.

    The syntax for this value is ncacn_ip_tcp:FQDN. For example, if your Exchange back-end server has a host name of EXCHANGE1 and the FQDN is, use the following value for ncacn_ip_tcp:

  6. Click OK two times to apply the change.

  7. Restart all Exchange Server services on the server.

  8. If there are multiple domain controllers, wait for replication to occur before you try to log on from the front-end server. If the problem is not resolved after replication is complete, restart the IIS Admin Service on the front-end server.

If you maintain host files on back-end servers to correlate a server IP address that has a short host name, you must also update the UpdateProtocols registry value. If a host file is used, Exchange Server may change back the ncacn_ip_tcp value when Microsoft Exchange System Attendant is restarted. If the back-end server is clustered, Exchange Server may change back the ncacn_ip_tcp value after fail over.

This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore the registry if a problem occurs. For information about how to restore the registry, view the "Restore the Registry" Help topic in Regedit.exe or Regedt32.exe.
To modify the UpdateProtocols registry value for back-end servers that use host files
  1. Use a registry editor to configure the following registry value on the back-end server or servers: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeSA\Parameters\UpdateProtocols

    If the UpdateProtocols value is not present, you must create it. To do this, follow these steps:
  2. Open a registry editor and locate the following registry subkey: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeSA\Parameters\

    1. Right-click Parameters, point to New, and then click DWORD Value.

    2. Type UpdateProtocols, and then press ENTER.

  3. Right-click UpdateProtocols, click Modify, type 0 in the Value data field, and then click OK.

  4. If your network uses a Hosts file on the back-end cluster node, modify UpdateProtocols order of entry as follows:

    IPAddress to FQDN

    IPAddress to NetBIOS

    instead of:

    IPAddress to NetBIOS

    IPAddress to FQDN

  5. Restart all Exchange Server services on the server.

Before you edit the registry, and for information about how to edit the registry, see the Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows registry" (