The server was physically protected by the secret service due to it being in Bill Clinton's home, which he is one of the Presidents still protected by secret service for life, and Hillary also has secret service protection for life as his wife. Secret Service doesn't just leave the home unprotected while they are away, the home is STILL protected to ensure no one breaks in to put bombs or access protected records or anything else for that matter whether they are home or away. So it was under 24hr surveillance.Was that the server that was allegedly setup inside a house with bog standard locks and stuck in a cupboard?
Because if it was, that server had fuck all protection at both the virtual and physical level.
Also, although there was a crap ton of speculation and rumor this still remains true:
"No public evidence has emerged to indicate that hackers compromised Clinton’s private server, although the FBI did determine that some of the messages she sent from the server were exposed when someone hacked her aides’ personal email accounts. "

DOJ watchdog slams Comey for claiming Clinton’s server could have been hacked
No public evidence has emerged to indicate that hackers compromised Clinton’s private server.

There was never any evidence her server was ever compromised by anyone. There was an absurd about of misinformation going around about it though. The Former President and his family's home will be under Secret Service protection for life.