Hello, so I have a few questions about this subject, we are getting 550 errors from barracuda networks. It looks like it can two things but I'm not sure if the second one matters.
The first one is, the internal address of the server is a DMZ address (ie 192.168.x.40) translated by our ASA, when the server sends out header information, it gives the 192.168.x.40 in it's sender ID, this is likely to cause a problem correct?
The second one is, the same SMTP header calls it by it's full name EdgeTransport.contoso.com not mail.contoso.com. Would this cause issues with spf if the DNS says that IP address is the public one (Along with responding with the internally translated IP address). We have spf record for mail.contoso.com but not the Edge Transport server as it can't be seen by any DNS service.