“More miles than any previous Secretary of State”

As more classified emails from Hillary’s personal server came to light today, I began thinking back to that big claim to fame for her time as Secretary of State – “she traveled more miles than any previous Secretary of State”.  Was she using this private server while she traveled too?  How secure was that set-up?  What kind of security implications does all that foreign travel present, if she was using her home-brewed server to conduct all of her business as Secretary of State?