How to create and manage an RDNS Blacklist Server


MailEnable can configure its SMTP connector to undertake Reverse DNS Blacklist checks against commonly used Reverse DNS Blacklist Servers. These include blacklist like Spamcop, Spamhaus, etc. MailEnable also allows you to define other DNS Blacklist providers.


In some cases, it may be desirable to run/manage your own DNS blacklist. In this case, you need to configure your own DNS server to contain Reverse Lookup Zones for the IP addresses in question. You must manage your own DNS server to do this.

For example, the following steps would allow you to define a blacklist entry for the IP address

  • From the Explorer menu, select Start|Programs|Administrative Tools|DNS to open the Microsoft DNS Manager
  • Right Click on Reverse Lookup Zones, and select the option to create a new zone
  • Set the Zone type as a Primary Zone
  • Enter the network ID as 192.168.55 (which will create a zone that contains all IP addresses under within that range)
  • Leave the option checked to create a new file with the name of the lookup zone
  • If prompted, select the value to not allow dynamic updates
  • Right click on the newly created zone (in this case named 192.168.55.x subnet) and select the option to create a new PTR record

    Enter the last numeric values of IP address in the space allocated and give the IP address an optional meaningful nodename eg: spammer  The next step is to configure the new RBL backlist under MailEnable's SMTP connector.

    Do this as follows:

    1. Select Add from the SMTP Connectors Reverse DNS Blacklisting page and enter a name that describes the DNS Blacklist being created.
    2. Enter the specific DNS settings for the server.  Do so as follows:
      - Enable Selected Blacklist = (Checked)
      - DNS Path: Host Lookup
      - Name Server = (IP Address of your DNS Server)
      - Check for record type = Pointer (PTR)
      - Response = "This IP address has been blacklisted"
    3. Click the Apply button to make the changes effective. 

  • Product:MailEnable (All Versions)
    Class:HOWTO: Product Instructions
    Revised:Wednesday, May 4, 2016