To successfully whitelist our phishing and training related emails when using MessageLabs or, you should add our IP addresses to a global Approved Senders list. This will allow our phishing and training related emails through. See this document (Symantec seem to have broken this link)or below:

To add a global Approved Sender: 

  1. Select ServicesEmail Services > Anti-Spam.
  2. Ensure that Global Settings is selected in the domains drop-down list.
  3. Click the Approved Senders tab.
  4. Click the Add Entry option.
  5. The Domain/Email/IP and Description fields become editable.
  6. In the Domain/Email/IP field enter the IP address of our mail servers. For the most up-to-date list of our IP addresses, please see this article
  7. In the Description field, enter brief details about the new entry.
  8. To add the entry to the list, click Update.

This new policy will allow any inbound mail flow originating from our IPs to reach your users. Be sure that all three of our sending IPs are added to this list.