Apple Resources - Public_Networks

  When one connects to a public network, one's device is
  typically provided with a Local IP address and a pair of DNS
  (Domain Name Server) IP addresses.

  Public networks such as WiFi at Universities, Airports,
  Hotels, Doctor's offices, Hospitals, Libraries, Coffee
  Shops, etc. ARE NOT SECURE. Any computer on those networks
  may have malware harvesting EVERYTHING you say, type and
  read. WiFi in retirement communities and apartment complexes
  may also be public networks. Find out!

  See what devices are on the network you are currently on:
  Mac: LanScan
  iPhone/iPad: Net Analyser Pro   

  In order to protect your privacy (and security) on a public
  network you should:
    1. Use a VPN (Virtual Private Network)  
    2. Use Public DNS (Domain Name Server)