I recently encountered an issue in vSphere 5.5 where I wasn’t able to change the interface speed on an ESXi host from auto-negotiate to anything else. After a good amount of troubleshooting I was able to determine that this issue was occurring due to the fact that the NIC firmware version and driver version on a blade server was out of date. VMware has a good KB article on how to grab the firmware and driver versions that I followed. However, the problem is that even on the most modest ESXi host that isn’t running 10G to it, you’ll likely have a minimum of 4 NICs on it. This means that you’ll have to enable SSH on every host you want to check, run one command per NIC each of them (or run a one line script that loops through them, but will that really save you time..?). It doesn’t take a very large cluster for that to become a very large endeavor.
This PowerShell script will connect to a vCenter server, allow you to scan all ESXi hosts, or only hosts within a particular cluster, and output the results in object format so that you can manipulate them how you wish.