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How to Request E-mail Relay Access

Relay access for an application (such as a hosted help desk system) or device (such as a multi-function printer) is available for CDS customers. Your request will be serviced by one of three instances of our high-availability SMTP relay appliances. They physical location of your application or device will determine which regional service you will use.

Information Required

To open a ticket with CDS Customer Care to request e-mail relay access, you will need to provide the following information.

  • The physical location of the application or device
  • The fully-qualified domain name of the application server or device
  • The public (external) IP address of the application server or device

If you do not know the public (external) IP address of the application server or device, you can visit our Support page from the application server. Alternatively, attempt to relay some messages to the appliances listed below and note the full time and date information as well as the sender, recipient, and subject line of the message. Provide this information in your request.

Configuration Information

LocationNameIP AddressPort

If your device or application cannot perform DNS name resolution, you may use the IP address instead of the name.

  1. Your application or device should be configured to use the SMTP server name of one of the appliances listed in the above table. CDS will let you know which one to use.
  2. It will always use port 25 for relay.
  3. If your application or device supports TLS, please enable it.
  4. You do not require any form of authentication once your IP address has been whitelisted.


When requesting troubleshooting assistance, please provide the full non-delivery report or, for missing messages, as much header information as possible such as the sender, recipient, subject line, and approximate time the message was sent.