@Tom-Elliott @AUTH-IT-Center
Thank you both very much for the fast and detailed responses! NFS mountd was indeed the culprit. Port 20048 was allowed, but I wasn’t aware that this needed to be configured in the nfs.conf file. Confirmed that imaging is working now.

Thank you! My question has been answered. The server is connected to a KVM and is only a few steps away from where I work. I’m just following the general rule of only allowing what is necessary and since SSH isn’t necessary (yet), I’ll keep it blocked.

@Tom-Elliott Thank you for the response. That answers the question. I’ll consider the proposed workaround. I’m going to look into other options, such as keeping FOG on an isolated network, and the practicality of those options.