All US Department of State Email is consider Sensitive But Unclassified (SBU) which is the rest of the Government's Unclassified. SBU was put into place to ensure all communications were covered under the NIST guidelines and government regulations, Foreign Affairs Manuals, Pamphlets, etc. so that no one was able to legally conduct any business with private Email accounts.
State Department Email is normally conducted on MS Exchange Servers. If the mail is to the same server's users it says locally to that network segment. If it goes elsewhere to someone in State, then is stays in the Departments Cloud, if it goes outside, then it transits public servers. It is not improper to send Email to a public server. It is improper to send Department Business from its employees from public servers. State Department communications are encrypted and decrypted as it travels different paths. This encryption is to prevent compromise, and is for all SBU workstations and network communications.
The entire Obama administration has been caught using personal email to conduct official business. Just because they do this does not make it legal. They should all be given the Gen. Petreas Treatment and put in jail as felons.
Will the GOP have the guts to pursue this or will the felonious Clintons skate yet again ?