XFOR: Error Message Occurs When You Enable a User to Relay (258140)


The information in this article applies to:

  • Microsoft Exchange Server 5.5 SP2
This article was previously published under Q258140
IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SYMPTOMS

When you enable an individual user to use the relay functionality, the relay procedure fails, and the user receives the following error message:
550 Relaying Is Prohibited

CAUSE

This issue can occur when you enter the subnet mask as (or if the mask is set to) 255.0.0.0, 255.255.0.0, 255.255.255.0 or 255.255.255.255. If you click the Routing Restrictions button in Exchange Server Service Pack 2 (SP2) or later, you must enter a subnet mask.

RESOLUTION

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To resolve this issue, use either of the following methods:
  • Method One:
    1. Open the Internet Mail Service properties, click the Routing tab, and then click Routing Restrictions.
    2. Click to select the Hosts and clients with these IP addresses check box.
    3. Click Add, and then enter the user's IP address (for example, 123.123.123.123) in the IP address box.
    4. In the Mask box, set the subnet mask to 255.255.255.x, where x is the last octet of the user's IP address (for example, 255.255.255.123), and then click OK.
    5. Use the Services tool in Control Panel to stop and restart the Internet Mail Service.
  • Method Two:
    1. Open the Internet Mail Service properties, click the Routing tab, and then click Routing Restrictions.
    2. Click to select the Hosts and clients with these IP addresses check box.
    3. Click Add, type the user's IP address in the IP Address box, type any subnet mask in the Mask box, and then click OK.
    4. Use the Services tool in Control Panel to stop and restart the Internet Mail Service.
    5. Start Registry Editor (Regedt.32.exe).
    6. Locate and click the following registry key:

      HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIMC\Parameters

    7. Double-click the RelayAllowList value, delete the subnet mask and semicolon, (leaving only the user's IP address), and then click OK.NOTE: After you finish this procedure, if you open the Internet Mail Service properties, click the Routing tab, and then click Routing Restrictions, the Mask box is blank. To apply these changes, use the Services tool in Control Panel to stop and restart the Internet Mail Service.

MORE INFORMATION

For additional information on routing restrictions with Exchange Server 5.5, click the article number below to view the article in the Microsoft Knowledge Base:

196626 XFOR: Restricting Routing in the Internet Mail Service

Modification Type:MinorLast Reviewed:4/25/2005
Keywords:kberrmsg kbprb KB258140
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