XCON: Authoritative and Non-Authoritative Domains in Exchange 2000 (315591)

MORE INFORMATION

By default, Exchange 2000 is authoritative for an SMTP address space when the address space is added to a recipient policy. To observe this:

1. Start Exchange System Manager, expand Recipients, and then expand Recipient Policies.
2. Open the properties of the Default Policy.
3. Click the E-Mail Addresses tab, click New, and then click SMTP.
4. A dialog box is displayed that you can use to type an SMTP address space. A This Exchange Organization is responsible for all mail delivery to this address check box is also located at the bottom of the dialog box. If this check box is selected, Exchange 2000 is authoritative for that address space. If this check box is clear, Exchange 2000 is not authoritative.

When Exchange 2000 is attempting to deliver a message to a local address space (that is, an address space that exists on a recipient policy) Exchange 2000 tries to find the destination address in Active Directory. If Exchange 2000 cannot find the destination address, what occurs next depends on whether or not Exchange 2000 is authoritative for the domain.

If the server is not authoritative, Exchange 2000 seeks another route to that address space by checking connectors and the Domain Name System (DNS). If Exchange 2000 finds a connector with a matching address space, the message is routed to that connector. If Exchange 2000 does not find a connector, Exchange 2000 checks the DNS for a mail exchange (MX) record and routes the message to the corresponding host. If both methods do not locate another route for the message, a non-delivery report (NDR) is generated with a 5.4.0 error code, which indicates a name resolution issue.

If the server is authoritative, Exchange 2000 immediately generates an NDR with a 5.1.1 error code, which indicates that the destination address does not exist. You can modify this behavior by specifying a host to which unresolved mail is forwarded. To locate this setting:

1. In Exchange System Manager, expand the name of the Exchange 2000 server, expand Protocols, and then expand SMTP.
2. Open the properties of the SMTP virtual server, and then click the Messages tab.
3. A Forward all messages with unresolved recipients to host box is located near the bottom of the Messages tab. If you populate this box (with either a fully qualified domain name or an IP address enclosed in brackets), unresolved messages to authoritative domains are forwarded to the specified host, and no NDR is generated. This setting has no effect on domains for which Exchange 2000 is not authoritative.

For additional information about how authoritative and non-authoritative domains are used when sharing an SMTP address space, click the article number below to view the article in the Microsoft Knowledge Base: