Supporting Messaging Clients

Set Relay Restrictions on a Virtual Server

Exchange blocks computers from relaying unwanted e-mail through an SMTP virtual server. By default, all users and computers are blocked from relaying, except those that are able to authenticate.

Tip   If your virtual server is on the Internet, you should disable relaying in order to prevent your server from being used to propagate unsolicited commercial e-mail.

To remove relay restrictions from a virtual server:

  1. Start System Manager
    On the Start menu, point to Programs, point to Microsoft Exchange, and then click System Manager.
  2. Navigate to the SMTP virtual server.
    1. Servers
    2. Server
    3. Protocols
    4. SMTP
    5. SMTP virtual servers
    6. SMTP virtual server
  3. Right-click the SMTP virtual server, and then click Properties.
  4. On the Access tab, under Relay restrictions, click Relay.
  5. In Relay Restrictions, click either Only the list below or All except the list below.
  6. To add members to the list, click Add. Depending on your choice in step 5, this list will define who may or may not relay e-mail on this SMTP virtual server.

You can specify the following options in Relay Restrictions:

Option Description
Only the list below Only the computers listed below can relay messages through the SMTP virtual server.
All except the list below All computers can relay messages through the SMTP virtual server, except those listed below. This is set by default, along with Allow any computers which successfully authenticate to relay, regardless of the list above.
Add and Remove Adds and removes entries to the list of those computers either granted or denied relay access.
Allow all computers which successfully authenticate to relay, regardless of the list above Allows computers that meet authentication requirements set in the Authentication dialog box to relay messages to the SMTP virtual server. This is set by default.