Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool queries the Win32_PerfRawData_SMTPSVC_SMTPServer Microsoft Windows® Management Instrumentation (WMI) class to determine the value for the BadmailedMessagesHopCountExceeded key. The value of this key represents the number of messages sent to the Badmail directory because they had exceeded the maximum hop count. The Badmail directory is used to store undeliverable messages. For information about some of the other Badmail WMI counters, see the Exchange Server Analyzer Tool articles, SMTP message failure warning - BadMail messages general failure and SMTP message failure warning - BadMail messages NDR of DSN.

There are counters that increment when a message is sent to the Badmail directory for other reasons, as well, including a bad pickup file, no recipients, and triggered via event.

The Exchange Server Analyzer also queries the Win32_PerfRawData_PerfOS_System WMI key to determine the value for SystemUpTime.

If the Exchange Server Analyzer determines the value for the SystemUpTime key is greater than 0 and that the result of the value for BadmailedMessagesHopCountExceeded divided by the value for SystemUpTime is greater than 100, a warning is displayed.

This warning indicates that an average of 100 or more messages per day are marked as non-deliverable and stored in the Badmail directory because they exceed the maximum hop count. The maximum hop count is the maximum number of SMTP servers through which a message can travel on its way from the sender to the recipient. Each time a message travels through an SMTP server, a line of text representing the hop is added to the message header.

The optimal number of message hops varies depending on the topology of your network and your messaging needs. To prevent a message from being repeatedly misrouted (a condition known as a message loop) an administrator can control the maximum number of hops that is allowed. This can be done by setting a maximum hop count for the SMTP virtual server. In Exchange 2000 Server, the default hop count is 15. In Exchange Server 2003, the default is 30. A value of 30 for both Exchange 2000 Server and Exchange Server 2003 SMTP virtual servers is recommended.

Messages in the Badmail directory must be manually deleted. It is recommended that regular review and deletion of messages in the Badmail directory be a part of regular Exchange Server maintenance. Allowing the Badmail directory to grow without restrictions could consume all available disk space, and in turn cause Exchange databases to dismount.

To correct this warning

  1. Examine the messages in the Badmail directory to determine if the source of the message is internal or external. Messages in the Badmail directory are stored in ASCII format, and can be opened and viewed in Notepad or another text editor.

    • If the messages appear to be generated internally, you can examine the message headers to determine their origin.

    • If the messages appear to be generated externally, it may indicate that your Exchange Server is being used as a mail relay.

  2. Set the Maximum hop count value to 30.

    1. Open Exchange System Manager.

    2. Expand Servers, then expand an Exchange server, then expand Protocols, then expand SMTP.

    3. Right-click an SMTP virtual server (for example, Default SMTP Virtual Server) and select Properties.

    4. Select the Delivery tab, and then click Advanced.

    5. Enter the desired value in the Maximum hop count field and click OK to save the change.

    6. Click OK to close the Properties dialog box of the SMTP virtual server.

For information about how to control and configure relay options, see the following Microsoft Knowledge Base articles:

For more information about database dismounts due to insufficient free disk space, see Microsoft Knowledge Base article 321825, "Databases Become Dismounted Because of Lack of Disk Space" (