I had a hotspot set up on this Mac Pro 2013 to connect a Mac Book and iPhone. Now the hotspot has disappeared and I cannot find where to turn it on again.
Mac Pro (Late 2013), OS X Yosemite (10.10.3)
System Preferences > Sharing > Internet Sharing
You want to "share" your existing Ethernet connection to the Internet out over your Wi-Fi. this sets up a very simple software Router at a slightly different IP Address, typically something like 192.168.2.100. It will provide Addresses using DHCP, but does not support the most advanced encryption methods.
Do not pay any attention to the IP Address shown on your Mac Pro Host for the Wi-Fi -- that always shows a self-assigned IP Address even when it is working just fine.
Mac Pro 2013, OS X El Capitain: How do I turn Hotspot back on?
