For clarity I run FOG under centos running on ESXi 5.5. I don’t have this kind of issue.
I know this was a long thread and I kind of skimmed it.
When you setup your linux server you should set the network adapter to e1000, you can use vmxnet3 if you install the vmware tools first. Its always has been a pain to do so I just use the e1000 driver. I seem to recall a bug with the e1000 driver with either the GA release of 5.0 or 5.5 that caused the virtual nic to hang under heavy load. That issue was fixed with a ESXi update. Is you ESXi server up to date with patches?
Please help me understand you say you can’t access the FOG server. I understand if you can’t access it via the network, can you log into the console directly using vmware configuration client? Or is the vmclient frozen? If you can log in from the console then I would sure check the logs in /var/logs to see if there is any indication of what happened. I would also try to restart the network services (from inside the fedora OS) to see if you can get it back online. I have see where two hosts having the same IP address will take a server off line like this.
It would be interesting to see what happens to this vm if you shutdown all FOG services at the end of the day. Is the VM still on the network in the AM?
[soapbox] While I understand the techie needs to run fedora, why are you using a desktop OS instead of a server OS? Would you load MS SQL server on Windows 7 for your enterprise application? Please pick stable rhel or centos over fedora. Yes I know it works, but why not use the right tool for the job.[/soapbox]