How to Customize Responses to E-Mail Rejected by an IP Block List

Exchange 2007

Microsoft Exchange Server 2007 will reach end of support on April 11, 2017. To stay supported, you will need to upgrade. For more information, see Resources to help you upgrade your Office 2007 servers and clients.


Applies to: Exchange Server 2007 SP1, Exchange Server 2007 SP2, Exchange Server 2007 SP3

Topic Last Modified: 2015-03-09

In Microsoft Exchange Server 2007, when you send an e-mail message from a computer whose IP address resides on a Block IP List, you receive the following error message:


550 5.7.1 Recipient not authorized, your IP has been found on a block list.

If want to provide more detail in the error message, you can change the default message to include the following information:

  • IP address of the sending Mailbox server

  • Rule name of the connection filter

  • The Real-time Block List Provider

To change the default message response
  • From the Exchange Management shell, use the following syntax to customize the Block List response:

    Set-IPBlockListProvider -Identity <providername>  -RejectionResponse: "My custom response {0}, your text {1}, more text {2}"

    Where the following is true:

    {0} = IP address sent in the query

    {1} = IP Block List Provider Name

    {2} = Lookup Domain (provider.LookUpDomain)


    For example, use the following syntax:

    Set-IPBlockListProvider - Identity Contoso -RejectionResponse: "Your message was rejected because the IP address of the sending server {0} is blacklisted by {1} Lookup Domain {2}"