Log into the setup screen by opening your browser and going to 192.168.1.1, then logging in. (You did remember to change the user name and password, didn't you?) Click the Wireless tab and look for the Wireless Network Name (SSID) box. Enter the new name of your network. On the same screen, look for the Wireless SSID Broadcast setting, and choose Disabled. Then, click Save Settings. That's all it takes. Again, if you have another model of router, your steps will be different.
Keep out intruders using MAC address filtering
With MAC address filtering, you can tell your network to only allow specific devices to connect, and ban all others. Every piece of networking hardware has a unique MAC address. So you'll be able to tell your router to allow only specific MAC addresses onto the network, and ban everyone else.
First, find out the MAC address of all of the wireless devices that connect to your network. How you do this varies according to your operating system, so you do it differently for Windows, Mac OS X, iOS, Android, and Windows Phone. There's no room in this blog post to give you the details for each. So head here or go here for solid information about how to find that all out.
Copy down all the MAC addresses of the devices. (They'll look something like this: 00:08:A1:00:9F:32.) Now log into your router and configure MAC address filtering. Again, this varies according to manufacturer and model. But on many Linksys routers, log in, then choose Wireless-->Wireless Mac Filter. On each entry box, type in the MAC address of a device. Click "Permit PCs listed below to access the wireless network." Then click Enabled. Finally click Save Settings.
Note that you you may find that some devices may be kicked off your network after you do this. If so, it means that you've either copied down their MAC addresses incorrectly, or simply forgotten about them. So double-check the MAC addresses of devices that were kicked off. If you have gaming equipment or entertainment devices such as a Sonos sound system, make sure to include their MAC addresses.
Spoof a MAC address to test your security
Want to make sure that your MAC address filtering is working? You can spoof the MAC address of a PC -- change its address to something different. After you've spoofed the address on the PC, try to connect to your network. If you get through, you've done something wrong with your MAC filtering.
To spoor a MAC address, get the free Technitium MAC Address Changer. It's simple and straightforward to use. After you've spoofed it, try connecting to your network.