If you do much work with copying ISO files to and between your VMWare ESX servers you may want to check out Veeam’s FastSCP utility. I have used this utility before and can confirm that it certainly does what it says on the side of the tin. One of the best features being that it’s free!
Veeam FastSCP is a fast, secure and easy-to-use tool to perform file management in ESX environment. FastSCP allows a user to copy files from ESX to Windows, Windows to ESX or ESX to ESX. This is the most natural way to deliver an ISO file to ESX Server, make a backup copy of an existing virtual machine (VM) or copy VMs and templates between ESX servers. FastSCP ensures security by using a one-time password feature and works over 6 times faster than SCP.