It's always a nice thing to find an open WiFi hotspot when you're out and about and it would be swell to play that forward and setup an open, informal WiFi hotspot of your own. Your visitors will appreciate it, certainly, but on the other hand you don't want to open your own LAN for just anyone to access.
It's pretty easy to set up an informal, but separate, "walk-in-and-use-it" WiFi hotspot that vistors can use to connect to the internet but that won't overtly expose your LAN connected computers, servers and printers to your guests.
All that you need to do this is a WiFi router set up to run a WiFi LAN that is separate from your home or business LAN.
Note please that I'm not using the word "secure" for this. If you truly require a definite and secure separation between your main LAN and the one that your guests will use, you'll need a more rigorous, complex and costly solution. But if "separate" is OK for your need, then this is the way to go.
Parts needed: an extra WiFi router. That's it.
Fancy or cheap -- doesn't matter. In fact, it may be easiest and cheapest to buy a surplus "B" class router on eBay or Craigslist. "B" class is fast enough for casual internet access to check email or make a Google search. Setting your guest LAN to run as class "B" has a couple other benefits too, but we'll touch on those later.


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