Years ago they used to call it war driving; roaming the neighbourhoods with a laptop, a wifi card and sometimes a high gain antenna. All in the pursuit of a free internet connection.
They even tried to make it illegal in some states. There are plenty of reasons why we did a mad scramble to find ways to lock down our wifi; liability risks of how people were using our internet connection and to protect our precious and often limited bandwidth.
Now a days we walk into coffee shops and restaurants to see stickers on the windows offering free wifi. 
An effort to promote the place as a great space to work away from the office. As I sit here at the mall which has a public skating facility, watching my wife and one of our boys do some laps around the rink, I struggle to find a public access wireless to use and I feel cheated.
So where am I going with this? Well there are a lot of movements to make church spaces attractive and useful for the other 6 days of the week. Our church has a nice sized cafe that we want people from the community to feel they can come out and grab a coffee and get some work done in a quiet setting. But what do we do with the wireless to protect our liability and our precious bandwidth?
There are a couple of ways to address this issue. In regards to bandwidth you could purchase a second internet connection dedicated to your public wifi. This method protects your network and your bandwidth from people on the public wifi for a small monthly fee. Depending on the amount of people using your space you could size your dedicated internet connection accordingly. If a second internet connection is not possible (we are located outside of the city limits and there is no DSL or Cable) you could setup a smart switch with virtual lans to keep your networks separated yet combine them at the firewall to connect to the internet. A good smart switch will also allow you to specify bandwidth limits on each port allowing you to allocate a portion of your internet connection to the public wifi and still secure a portion of it for your own office staff. If your on a corporate internet service, you might even be able to setup a second firewall and have a dedicated IP address from your internet provider, thus making two discrete networks out of one.
So that covers the separation of networks and protecting your bandwidth and your office network, how do you go about protecting your liability, remember this is still your internet connection and you could be liable for how people are using it. Or worse, have to explain how a computer on your network uploaded some inappropriate content to a file sharing site. While I wish I could offer you a guaranteed solution, the best thing we can do is take the necessary measures to do the best we can. At a basic level we should be using a DNS filtering service like OpenDNS to limit access to certain types of sites. This service will breakdown the sites into various categories like adult, weapons, hate crimes, vacations, file sharing, etc that you can block access to on a category by category basis. If you want to get more control over your public wifi you could look at putting in a captive portal like WiFiDog, this gives you the ability to make temporary user accounts for everyone connecting to the wifi similar to what you might find at a hotel or coffee shop. Another option is NoCatAuth or at a minimum use the NoCatSplash so you can present the user with the terms and conditions of using the free public wifi.
So to answer the original question, should your church offer public wifi? I won’t give a unanimous yes, but if it fits the facility use plan that your church has and you take the time to implement it properly.
