How can I block neighboring wireless networks?

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Summary: Accidentally connecting to someone's nearby wireless network can be a serious security risk. We'll look at some steps to prevent it.

A neighbor has kindly named his unprotected wireless network after my own. I'm not sure why but it must be intentional since my network name is rather contorted. I immediately changed my network's SSID and increased the security level to WPA-TSK. However, as the neighbor's network has a strong signal and is unprotected, my laptop insisted on logging on to it until I realized what was going on and deleted it from the preferred nets list. However, I would feel safer if I could simply block the said network altogether. Is that possible?

By the way, could this be what I think it is? The neighbor setting up an unprotected network with the same name as mine in the hope that my computer would connect to his net if mine happened to be down?

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This is a very interesting scenario. On the surface it certainly feels like your neighbor is up to something. Exactly what is difficult to say, but I think you're wise to be very cautious.

While I wouldn't call it "blocking" the neighbor's wireless network, here are the steps I would take...

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You've already taken the first step... enabling some form of encryption. WEP would be good, but WPA, as you've selected, is better still. WEP was found to be more easily crack-able, and given that your neighbor appears to be at least somewhat technically savvy, and perhaps has bad intentions, using WPA is the better choice.

The next step I would take would be to make sure you connect only to your preferred connections. Again, it sounds like you may already have done this. In Control Panel, Network Connections, right click on your Wireless Network Connection and click on Properties:

Wireless Network Properties Dialog

Click on the Wireless Networks tab:

Wireless Network Properties Wireless Networks Tab Dialog

Scan through the Preferred Networks list. For each network listed that you don't recognize or you know should not be trusted, click on it and then click on the Remove button.

Now click on the Advanced button:

Wireless Network Properties Wireless Networks Tab Advanced Dialog

Make sure that "Access Point (Infrastructure) networks only" is selected, and that "Automatically connect to non-preferred networks" is unchecked.

"Configure your access point to stop broadcasting the SSID ..."

Now, at this point I'm assuming that a network is "identified" by both its name and its encryption status. So that if your network, with WPA enabled, is on your preferred list, then you won't automatically connect to your neighbor's unprotected network of the same name if yours is down. Obviously that's easy to test.

But there's one last thing you didn't mention, that while not absolutely secure, could be an additional level of protection, and if broached would confirm your neighbor's bad intentions.

Configure your access point to stop broadcasting the SSID (aka network name), and then change the SSID. Unfortunately, exactly how this is done depends on your specific access point.

The down side here is that Windows won't automatically detect your network ... you'll have to configure it manually in the Wireless Networks Tab shown above. Just hit the Add button and you'll be able to enter the SSID by hand:

Wireless Network Properties Wireless Networks Tab Add Connection Dialog

It also means that your neighbor won't see your new network name - at least not easily. And that's why I say it's not absolutely secure. If your neighbor is technically savvy enough to sniff your wireless packets, the SSID can still be viewed. But in that case, if another open access point appears with your new "hidden" network name, you'll know that your neighbor is up to no good.

Related:

Ask Leo! - Wireless Encryption: do I need it?
Ask Leo! - How do I determine the capabilities of my wireless network adapter?
Ask Leo! - How do I connect my desktop to the nearby wireless internet WiFi hotspot?

Wikipedia - Service Set IDentifier (SSID) - a good overview.

Article C2914 - January 30, 2007

Recent Comments

18 Comments

Isn't there an issue with wireless networks that are deleted from the preferred networks window, again re-appearing in the same window at some point in the future? Seems I've seen that before. Right now I've not seen a way to restrict these adjacent wireless networks from being discovered by a wireless laptop. And that can be a pain sometimes for the very issue the original poster was writing about.

One thing you can do is to make sure that your "absolute" preferred network, is at the very top of this list, as that will be the first one that your wireless device will attempt to connect to -

Posted by: Hal M at February 3, 2007 6:09 AM

One other note, is most wireless setups will default to running on channel 6 for their wireless communications frequency. I'd go in and change from the default 6 to channel 11. You have to do that within your wireless router and laptop wireless adapter. If the guys neighbor is running ch6 and your original poster changes his setup to run on ch 11, that may help with his wireless always attemtping to connect to the neighbors network.

Posted by: Hal M at February 3, 2007 6:19 AM

OK, pretend I'm really thick and explain something to me in easy-to-understand words:
What is the problem with having a neighbor with this unsecured wi-fi? Isn't it the neighbor who is at risk by doing what he's doing, and not the person above?
Thanks.

Posted by: Sam at February 4, 2007 8:53 PM

If the neighbor is technically savvy, he could sniff your network traffic if you connect through his access point.

(And yes, if it's an accident, it's the neighbor at risk of being snooped by whoever can connect.)

Posted by: Leo Notenboom at February 4, 2007 8:56 PM

This neighbors intentions were probably far more nefarious and possibly illegal. He was hoping that your computer would connect to his wireless device. He could then use that connection to monitor the traffic that was passing through it. I cam see no other reason for the neighbor to name his network the same as yours.

Posted by: Philip C Tyson at February 6, 2007 5:23 PM

It's interesting that the neighbor is assumed to be technically savvy enough to intentionally try to access the OP's system. I know many intelligent people who have great difficulty with basic network configuration. My initial thought was that said neighbor did not previously have his own internet connection and had been utilizing the OP's network. Then in a befuddled attempt to try and make a new system work, he simply renamed his network to that which he had been using. Perhaps I'm being Pollyannaish, but I've seen enough people do wacky things that it's a possibility.