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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?

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...

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.

Article C2914 - January 30, 2007 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

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29 Comments
Wesley Griffin
January 30, 2007 1:14 PM

A very timely acticle. I have just upgraded to
wireless, and right off experienced an
unprotected wireless network that overpowered my
system. I am not that familiar yet with Wireless Networks, WEP,or WPA .Could you go into some detail on WEP or WPA in another article.
Is their any third party 'blocking utility' available that would protect you from this.
My service provider was of no help.
Thank's for a very informative article.

Dave Peters
January 30, 2007 8:43 PM

I would also like to add to the article an important point that was missed. When setting up your passphrase with WPA, it's so important that you have a 'Strong' password. I graduated last year with a networking degree and one of the things we did in our wireless class was to break into WEP and also WPA. In fact, I think WPA can be easier at times to break into. The way we did this was a dictionary attack. There are plenty of articles on the net using linux on how to do this. So make that passphrase strong, and you shouldn't have many problems.

Ken
January 31, 2007 9:38 AM

Regarding the disabling of SSID broadcast...

You can change the SSID prior to disabling the broadcast, allow your system(s) to detect it and configure the connection, and then disable the broadcast. This is a lot easier than manually configuring it when renaming it after disabling SSID broadcast.

Of course, it does leave a window of opportunity for your neighbor (and others) to see the new SSID, so you need to weigh the convenience versus the security.

Sergio Coelho
January 31, 2007 7:13 PM

Thanks for the thorough explanation and the advice. Sounds like a good idea to hide the SSID -I just need to check if the router allows it (but since I'm about to get a faster one, I'll pick one that does). As I live in an apartment block and there are a couple dozen diferent signals appearing on the wireless detector, if mine goes anonimous then I cannot see how the said neighbor can easily pick anything up in the middle of all the others.

Carl
February 2, 2007 6:08 PM

Sounds like a "For Sale" sign might be necessary in the near future???

Jim S
February 2, 2007 7:32 PM

I'm curious as to why you didn't recommend limiting the MAC addresses that the router would allow to connect?

Jim S
February 2, 2007 7:32 PM

I'm curious as to why you didn't recommend limiting the MAC addresses that the router would allow to connect?

Dave Peters
February 2, 2007 9:19 PM

If I remember correctly from my classes, the tools we used was able to view the MAC addresses of all the computers that are attached to a network. Once you have that, there are another set of tools you can use to spoof your own MAC address. Once you have spoofed your own MAC, you then have the rights to login to the network; provided you have used the other tools correctly to get the WPA passphrase. Again, I can't stress enough a Strong Passphrase.

Hal M
February 3, 2007 6:09 AM

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 -

Hal M
February 3, 2007 6:19 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.

Sam
February 4, 2007 8:53 PM

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.

Leo Notenboom
February 4, 2007 8:56 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.)

Philip C Tyson
February 6, 2007 5:23 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.

Kristin
February 9, 2007 3:31 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.

ANDRE
November 13, 2007 7:51 PM

REF: How can I block neighboring wireless networks?

Would you have an answer for VISTA 32 bit ? the wireless properties dialog box is different...

Thanks

Nikki H.
March 31, 2008 11:46 AM

Good subject...!
I was also wondering about how i can block out my neighbors WiFi signal.
I must admit that i don't have a wireless signal at my house & i sometimes use my neighbors
unprotected 'linksys' signal. I want to have access to that network when i need to use it
(for email, banking, etc) but i also want to prevent my son (who is 13) from accessing the network because he
has dabbled in looking at inappropriate stuff on our family desktop (i have already used netanny & cybersitter
to try to discourage him from looking at inappropriate content, but he always finds a way around it, so i've
realized that completely restricting his access to my neighbor's wireless signal is the only sure way to remedy
this problem). Is there a way for me to use my neighbor's signal when i want to... & also to be able to restrict
it when my son is alone at home? Thanks for your advice. I run windows VISta on all the family computers.

Michael
August 18, 2009 6:01 PM

I have a slightly different situation. i want to set up my computer so that it is unable to detect an incoming signal from a neighbors network.

for example, lets say i have a content filter, but if my kid connects to my neighbors unsecured network from his laptop he can bypass it. .. so what i need is to configure his machine so that when he opens his network connection center he cant even see the neighbors signal ..

if you have any suggestion please feel free to email me. thanks

Michael
August 18, 2009 6:05 PM

sorry, let me add, the laptop needs to be able to recognize other networks at school, coffee shops, etc. i'm just looking for a way to prevent windows from detecting one specific network. from the way i understood your article, if unchecking the box to recognize non-preferred networks would not be ideal for this reason. i hope i'm not confusing the issue

John
January 9, 2010 6:18 PM

When you speak of sniffing, can the neighbour actually view or guess what you are viewing on or doing on the internet if you connect to his wireless network?

Yes.
Leo
10-Jan-2010

sherri
January 9, 2010 6:28 PM

Can you explain how to do this with Windows 7? Everytime my computer brings up the neighboring networks and my own, but I would rather just see my own. Thanks!

sneaky
January 21, 2010 4:49 PM

beings they have their network open they prolly dont have a password on the administration of the router so try changing the name of the router yourself lol
look up default router passwords also

Mitch
July 2, 2010 2:36 PM

I need to know if I can prevent my kids from connecting to the neighbors wifi. we have a content filter on our router but if they connect to neighbors there is no filter. I would just like to block this one wifi network so my kids cannot connect to it

Nope. You need to ask your neighbor to secure his WiFi with a password.
Leo
03-Jul-2010

Nancy
August 15, 2010 12:12 PM

From another board:
"What I have done:
- add your neighbors network as a preferred network to the computer and in the wireless configuration, select WEP protection and enter a WEP key. When the kids try to connect to the network it will simply time out because your computer will try and secure the connection using the WEP key you entered but it will fail since it is actually a non-secure network. I have three kids 17, 15, and 12 and they were connecting to the neighbors network to get around my security but this little setting has resolved that issue. The problem will be if they are very computer savvy they may figure it out."

Clare
November 22, 2010 1:28 AM

Can someone please give me some tips: My mum wants to buy me a touch screen phone but she does not want it to have WiFi in case i use it all the time and not focus on my studies.Is there a way to prevent me from connecting to my house wireless network?

She can put a WPA password on the wifi and not tell you. Not sure how this helps though since you can still do everything through the phone's celluar connection
Leo
22-Nov-2010

Toll Sam
January 29, 2011 6:55 AM

Hi
I have same your problem, but I need a solution in Windows 7, I'm trying to find wireless network tab in network connection properties but noway..
so I need to help me.
Another question:
My neighbor has a wireless card and him trying to access to my computer by using my wireless card, additionally I can see his computer name in my wireless connection list, so how I can block his computer to access to my computer.
Many thanks

Dan The Man
May 20, 2011 8:28 AM

Let's turn this around. If I was at home, connected to my home network via an ethernet cable but my wifi was switched on, is it technically possible for my laptop to connect 'accidentally' (without my knowledge or active intervention) to an open SSID (e.g. a neighbour) and then for a host on that network to get access to anything on my laptop or network? I really don't think so, but I don't know whether there are any superduper vulnerabilities.

Not normally, no. You'll see it listed as an "available network", but unless you say "connect" it should not. The one caveat is that if you connect to it once on purpoase, then it's possible that Windows may automatically connect again in the future unless you turn off "automatically connect" for that network.
Leo
24-May-2011

Charlotte
November 24, 2011 1:29 PM

Can my roommate "steal" wi-fi from my desk top computer? How can this be prevented. So many issues now with her. Quit job for no reason, lazy. All she wants to do is be on her laptop! Please help.

Connie
November 24, 2011 9:18 PM

@Charlotte
Yes. She can definitely "steal" wifi if you do not have it
secured and password protected from her. Assuming, as a
roommate, she is sharing your living quarters she might also
be able to use your internet connection without the wireless
simply by plugging into it with a LAN wire.

Here is an article on securing your router:
Securing Your Router

Poida
July 17, 2012 5:29 AM

Very interesting back in nineteen-o-dot, but these windows/settings don't exist in windows 7

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