I'm getting an increasing number of messages with "Reverse DNS for x.x.x.x failed." We don't have a Reverse DNS record setup, and I need to. When I check the headers sent from my organization to a test gmail account I've set up, the FQDN is the internal FQND of the machine's host name on my local LAN, not an FQDN associated with the internet domain name of our organization. Upon review this seems incorrect, but would like to solve this. What should the FDQN in the header actually be? Where do I change this in Exchange 2013, and what impact will that have on mail flow as soon as I do change it? I would imagine once this issue is corrected, I can create the proper PTR/Reverse DNS record and all will be well. Any info would be helpful, thanks!