Microsoft KB Archive/251149

= Guest Account Allows Relaying Regardless of Routing Restrictions =

Article ID: 251149

Article Last Modified on 10/25/2007

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APPLIES TO


 * Microsoft Exchange Server 2003 Enterprise Edition
 * Microsoft Exchange Server 2003 Standard Edition
 * Microsoft Exchange 2000 Server Standard Edition
 * Microsoft Exchange Server 5.5 Standard Edition

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This article was previously published under Q251149



SYMPTOMS
The Internet Mail Service could allow non-authenticated users to relay mail if the Microsoft Windows NT domain Guest account is enabled.



CAUSE
This problem may occur if non-authenticated users bypass routing restrictions that require authentication by using the Guest account. After Simple Mail Transfer Protocol (SMTP) authentication does not work, some clients use the Guest account.



WORKAROUND
To work around this problem, disable the Guest account. To do so, use one of the following methods.

Method 1

 * 1) Start the Active Directory Users and Computers snap-in. To do so, click Start, point to All Programs, point to Administrative Tools, and then click Active Directory Users and Computers.
 * 2) Click User, and then double-click Guest.
 * 3) Click Account, click to select the Account Disabled check box, and then click OK.

Method 2

 * 1) In Windows NT User Manager for Domains, double-click the Guest account to select it.
 * 2) Click to select the Account Disabled check box, and then click OK to save the changes.

Additional query words: XIMS IMS IMC relay netscape

Keywords: kbprb KB251149

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