How to configure the SMTP connector in Exchange 200x

In Exchange 2000 and Exchange 2003, the Simple Mail Transfer Protocol (SMTP) connector replaces the Internet Mail Service in earlier versions of Exchange for mixed mode environments. However, it should be noted that in pure Exchange 200x environments, a connector is not a requirement for Internet mail flow. This article explains how to configure the SMTP connector.

Exchange 2000 and Exchange 2003 work differently than Exchange Server 5.5. SMTP is an add-on to Exchange Server 5.5 through Internet Mail Service. SMTP is native to Exchange 2000 and Exchange 2003. Everything is SMTP-based. The default SMTP virtual server, by itself, can handle all Internet traffic (inbound and outbound).

Typically, the main reason for an SMTP connector is either to send mail a certain way to a certain domain (for example, to forward messages to a specific smart host for that domain only or to send HELO instead of EHLO) or to take the place of an IMS in an environment that includes Exchange Server 5.5.

To create and securely configure the SMTP connector follow these steps:

1. Start Exchange System Manager.
   
   Note After you install Exchange Server in an Exchange 2003 organization or in an Exchange 2000 organization, Exchange System Manager does not automatically display routing groups and administrative groups. You must configure the Exchange organization to display routing groups and administrative groups.
   For more information about how to configure Exchange System Manager to display routing groups and administrative groups in Exchange server, click the following article number to view the article in the Microsoft Knowledge Base:
   312411 How to configure System Manager to display routing and administrative groups in Exchange 2000 Server
2. Expand the Administrative Groups container. To do so, click the plus sign (+) to the left of the container.
3. Click the administrative group that you want to work with, and then expand it.
4. Expand the Routing Groups container.
5. Click the routing group that you want to work with, and then expand it.
6. Click the Connectors container. Right-click the Connectors container, and then click New.
7. Click SMTP Connector.
8. On the General tab, provide an appropriate identifying name for the connector.
9. Choose to use DNS or forward to a smart host (if you are relaying through an Internet service provider send-mail server). If you are forwarding to a smart host, use the IP address of the smart host in square brackets.
10. Under Local Bridgeheads, click Add. Add the server that becomes the bridgehead server for the routing group. Designate an SMTP virtual server as a bridgehead server for the SMTP connector. This can be either the server that you are working on or another server in the same routing group. Alternatively, this duty can be shared by multiple servers.
    
    Important You can configure an SMTP virtual server to use a TCP (Listening) port that differs from the default SMTP port 25. You must make sure that the SMTP virtual server that you select as a local bridgehead for the SMTP connector has a TCP (Listening) port that equals 25. When you do this, the SMTP virtual server can be reached by other SMTP virtual servers that have the default TCP (Outgoing) port 25. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
    274842 How to change SMTP port 25 to another port in Microsoft Exchange Server
11. Click the Address Space tab. Under Connector Scope, click either Entire Organization or Routing Group. As in earlier versions of Exchange Server, when you configure the Internet Mail Service, click Add, click SMTP, and then click OK. Accept the default (*) unless you require outbound e-mail domain restriction, and leave the cost as 1. If you have accepted the default of (*), you should never click to select the Allow messages to be relayed to these domains check box. Clicking to select the Allow messages to be relayed to these domains check box would open your server for relay to the world. The Allow messages to be relayed to these domains check box should be for secure domain to domain connections only.
12. If you have chosen forward all mail to a smart host, click the Advanced tab. Click the Outbound Security option, and then select an appropriate authentication method for your relay host. The default is Anonymous Access. Anonymous is the method that must be used if you are forwarding to an ISP, unless you have made prior arrangements with the ISP for another security level. If you are forwarding to your own server or to another server outside your environment, work with the administrator of that server to select the appropriate security level for both servers. You can add more than one smart host in this box by using the following format:
    [IP];[IP];[IP];[IP]
13. Click OK to exit Outbound Security.
14. Click OK to exit the Advanced tab.
15. Click OK to exit the SMTP connector.
16. You must restart the Microsoft Exchange Routing Engine service and the SMTP service for these changes to take effect.