XFOR: How to Configure the Internet Mail Service to Accept Mail Without a Domain Name System Entry

Normally, a mail exchanger (MX) record is used in a Domain Name System (DNS) to allow other Simple Mail Transfer Protocol (SMTP) senders to locate the Internet Mail Service for incoming e-mail. If you cannot create an MX record, you can accept e-mail as either user@server.domain.com or user@IPaddress, in accordance with the IPv4 literals requirements of Request for Comments (RFC) 821. This article explains how to accept e-mail as either user@server.domain.com or user@IPaddress.

The following are the requirements to accept e-mail as user@server.domain.com or user@IPaddress, as applicable:

• To accept mail as user@server.domain.com, you need an address record, also known as an A record, for the server in the DNS.
• To accept mail as user@IPaddress, you need a computer running Exchange Server 5.5 and a static IP address for the Exchange Server computer.

Set up the Internet Mail Service to accept connections for the appropriate IP or DNS record:

1. In the Exchange Server Administrator program, click the site Configuration container, and then click Connections.
2. Click the Internet Mail Service for the server and open the Internet Mail Service properties.
3. Click the Routing tab.
4. Make sure that Reroute incoming SMTP mail is selected.
5. Add an entry for either server.domain.com or for the IP address, and then click to select the Should accept as inbound check box.
6. Click OK to close the Internet Mail Service properties.

Set up users with e-mail addresses of user@IPaddress or user@hostname:

1. In the Exchange Server Administrator program, click the site Configuration container, and then click Site Addressing.
2. Open the Site Addressing property page and click the Site Addressing tab.
3. Change the default SMTP address to servername.domain.com or the IP address.
   This changes the SMTP addresses of all of the users. To set up multiple proxy addresses for all of the users, you need to either edit user addresses individually, or use an import file format that adds an SMTP secondary proxy address.For additional information about this import file format, click the article number below to view the article in the Microsoft Knowledge Base:
   155594� XADM: Generic Import Format to Add SMTP Secondary Proxy Address
4. Click OK to close the Site Addressing property page.

IMPORTANT: You may not be able to deliver mail to some servers without a DNS entry for your server. For additional information, click the article number below to view the article in the Microsoft Knowledge Base: