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XCON: How to Prevent Mail Relay in Exchange Server 5.5 SP1 or Later
Article ID: 315687 - View products that this article applies to.
This article was previously published under Q315687
This article describes how you can configure the Internet Mail Service (IMS) in Microsoft Exchange Server 5.5 Service Pack 1 (SP1) or later to stop relaying unsolicited e-mail (spam). This configuration does not prevent Post Office Protocol version 3 (POP3) clients and Internet Message Access Protocol version 4 (IMAP4) clients from sending Simple Mail Transfer Protocol (SMTP) messages.
NOTE: Exchange Server 5.5 Service Pack 1 (SP1) permits you to set restrictions on routing.
To set restrictions on routing, follow these steps:
Additional Routing Restrictions
Hosts and Clients That Successfully AuthenticateYou can use this setting to relay only those messages that are sent from hosts and clients with valid logon information. If you have POP3 or IMAP4 users, each client profile must be set up to log on to the outgoing mail server.
To turn on outgoing server authentication in Microsoft Outlook or Outlook Express, follow these steps:
Hosts and Clients With These IP AddressesYou can use this setting to relay only those messages that are sent from a host whose IP addresses and subnet mask fall in the range that you specify.
Hosts and Clients Connecting to These Internal AddressesYou can use this setting to relay only those messages that are sent by hosts and clients that connect to specified IP addresses on the Microsoft Exchange Server computer. This permits multihomed servers to restrict message relay based on the IP address to which the client connects. If you select this option, you must turn off IP forwarding on the Networking property pages in Control Panel.
Specify the Hosts and Clients That Can Never Route MailYou can use this setting to stop the relay of messages that are sent from specified IP addresses and subnet masks.
Article ID: 315687 - Last Review: October 28, 2006 - Revision: 3.2