Applies to: Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2007-09-25

This topic explains how to resolve the problem of inbound Internet e-mail messages that are stuck in queues on the Edge Transport server when the Edge Transport server tries to send mail through Microsoft Internet Security and Acceleration (ISA) Server 2006, with Simple Mail Transfer Protocol (SMTP) filtering or Secure SMTP (SMTPS) filtering enabled, to internal Hub Transport servers. For more information about what causes inbound mail messages to be stuck on Edge Transport server queues, see Messages Queue on an Edge Transport Server with 500 5.1.1 Unrecognized Command Error.

The following procedure explains how to use Microsoft Management Console (MMC) in ISA Server 2006 to disable the SMTP filter or SMTPS filter to allow inbound Internet mail flow between Exchange transport servers in the perimeter network of your Microsoft Exchange Server 2007 organization.

You can use an alternative method that does not require disabling SMTP or SMTPS traffic on ISA Server 2006. The alternative method is to add Exchange 2007 SMTP verb commands to ISA Server 2006 so that inbound Internet mail can flow between the Exchange transport servers. For more information, see How to Add SMTP Verb Commands to ISA Server 2006.

Before You Begin

To perform this procedure, the account you use must be delegated the following permissions:

ISA Server 2006 edition Permission

Standard edition

ISA Server Full Administrator

Enterprise edition

ISA Server Array Administrator

Before you perform the following procedure, note the following:

  • The SMTP filter or SMTPS filter should be disabled only on those firewall policy transport rules that are published between the Hub Transport server and the Edge Transport server for mail communication.

  • The SMTP filter is applied to the Mail Server Publishing Rule created on ISA Server 2006 at the organization level. Unless the SMTP filter is disabled on ISA Server 2006 at the organizational node, you cannot disable the SMTP filter on firewall policy rules. For more information, see How to Disable the SMTP Filter or SMTPS Filter on ISA Server 2006 at the Organization Level.


To use ISA Server 2006 MMC to disable the filter on firewall policy rules

  1. In the console tree of ISA Server Management, select the Firewall Policy node.

  2. In the details pane, right-click the SMTP transport server rule that you created for the Hub Transport server, and then click Properties.

  3. On the Traffic tab, click Properties.

  4. On the Parameters tab, in the Application Filters list, clear the SMTP Filter check box, and then click OK.

  5. In the details pane, click Apply to save the configuration changes.

  6. Repeat the earlier steps on Firewall Policy rules if the SMTPS Server protocol is configured.

    At this stage, you may receive the following error: "This application filter is used by the corresponding protocol at the organizational level. Therefore it cannot be deselected."

    The error appears if the SMTP filter is not disabled on ISA Server 2006 at the organizational level. For more information about how to disable the SMTP filter, see How to Disable the SMTP Filter or SMTPS Filter on ISA Server 2006 at the Organization Level.
  7. Restart the Microsoft Exchange Transport service on the Edge Transport server.

    The inbound Internet mail queue on the Edge Transport server should clear.

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