This article applies to:

• Trustwave MailMarshal (SEG)
• Exchange 2010

Symptoms:

• Incoming messages for some users are rejected by Exchange
• Response (in MailMarshal Sender log): Server refused mail at END OF DATA - 554 5.6.0 Invalid content

Causes:

• The message is being blocked by a content filtering policy on the Exchange Server
• This could be an anti-malware plugin or IP filtering

Resolution:

• If you are using a third party scanning plugin on the Exchange server, check the configuration of the plugin.
• It may be useful to exclude the MailMarshal server from Exchange Sender ID and Connection Filtering. You can do this by editing the Transport Settings:
  1. In Exchange Management Console, navigate to Organization Configuration > Hub Transport > Global Settings tab.
     
     
     
     
      
  2. Double-click the Transport Settings item and select the Message Delivery tab.
      
     
  3. Add the IP address of the MailMarshal server to the list.
  4. Save changes.

Note:

• If this issue begins suddenly or applies to many users or messages, you should investigate the possibility that your MailMarshal server has been reported on a spam or malware reputation list.