Our organisation has implemented Mimecast for our email security. We have some users who are using a application and uses it to send out emails to other users of the same application.
However, we get emails bounced back, due to Mimecast detecting a different IP address everytime the email gets sent out via Messagelabs and sees it as spoofing when it is not.
Can anyone provide the IP Source Range for Messagelabs:
mail1.bemta5.messagelabs.com’s source IP range