I suspect someone may be highjacking my WIFI, what to do?

[roccenstein]

I have a Linksys WRT54G and I have it connected directly to my main PC.  I also have a second PC downstairs using a wireless card, and I have an XBOX 360 that I connect occasionally by network cable.  I periodically check my network connections using the Linksys Easylink Advisor and it usually always shows my PC, the one downstairs, and the 360, but today there are three new things listed there as being on the network that I don't recognize.  It's possible that two of them (that are labeled 'unnamed') are duplicates of my two pc's because I unplugged the router the other night as I was having some connection difficulties.  The third one, however, is named 'DEDWARDS-LT', and my name isn't D Edwards and I don't know anyone by that name.  When I click on them, I can only view the IP and see the name (if there is one).  How do I cut these off of my network?  I reran the security settings and have a fairly random SSID.  Anyway, I was hoping I could just highlight the offending ids and delete them, but it doesn't give me that option.  How do I get rid of them?

[Deerpark]

Use encryption for your wireless network. Then anyone who wants access needs to enter a password.

You might want to read this thread.
http://www.computerhope.com/forum/index.php/topic,40132.0.html

[2k_dummy]

Try limiting the number of IP addresses that the router will allow. If you have only 2 machines and no other wireless devices that use the router, limit it to 2 IP addresses. Once they have been assigned to your machines, no other connections will be allowed. Set them to be valid for 24 hours. You can then use a small .bat file that will renew the IP and shutdown the computer. As long as the computer is turned on at least once every 24 hours you should have no problem.

[Deerpark]

2k_dummy you seem to have misunderstood how a DHCP server works. Limiting the amount of IPs the DHCP server can assign doesn't prevent more IPs from connecting. You can just assign a static IP, outside of the DHCP pool, to the device you want to connect.
I use this on my home network to assure that my wireless AP always has the same IP.

[2k_dummy]

I'm aware of that, but much depends on the person connecting to the network and his knowledge of how it works. Since the person connecting left his name intact, I would venture to say that he does not have very much networking knowledge. If the IP's are assigned in an orderly fashion, you can almost bet that all of them are using DHCP and they are "chance" connections. Another thing that helps here is to disable SSID broadcast. If they don't know you are there, they won't connect. I know that you cannot deter a hardcore cracker, but the more bumps in the road, the harder it is to navigate. With wireless networking, one should employ as many strategies as are available.

[Deerpark]

The problem is, both the strategies you suggest are very small bumps that will only deter those who are just connecting to the network because they can. Wardrivers and others who know what they're doing will barely notice these obstacles. And in case someone uses your internet connection for illegal activities, it is your door the authorities will come knocking on.

So I am strongly against suggesting these makeshift solutions when securing the network properly only requires slightly more effort.
If you use encryption like WPA (or even better WPA2) it will take a long time to gain access to the network and in the end they will most likely go looking elsewhere for easier prey.

[roccenstein]

OK, I appreciate all the replies, but the problem is I don't know how to do any of the things you guys suggested.  How do I access my routers settings on my PC?  So far, the only way I know is by using the Linksys Easylink Advisor that I mentioned, but there aren't any options anywhere on that to do any of what you guys said.  One other thing, since I've noticed the extra connections, they've never been active (my router window displays all connections and they are highlighted if they are active) so I'm wondering if it was just a one time thing and the settings are just still there?  For the other connections it just shows unnamed device and a MAC address.

[2k_dummy]

I'm not suggesting that he not use encryption. I am suggesting little things that help to make it more difficult for casual connections. As I stated above, you can't stop a hardcore cracker if he wants in bad enough.

[roccenstein]

Use encryption for your wireless network. Then anyone who wants access needs to enter a password.

You might want to read this thread.
http://www.computerhope.com/forum/index.php/topic,40132.0.html

LOL, that's another thread I started, and I thought by following the setup directions with my router install and selecting all the 'higher' security settings that I was OK...

[Deerpark]

LOL didn't even notice it was your thread...
Okay I've found a manual for a Linksys WRT54G.
Download the user guide from here.
Give it a read... especially the first page in chapter 3 about how to access the configuration utility and then the section on wireless security.
You'll get the best protection if you use WPA2 Personal but your wireless devices might not support it. Try WPA personal if your devices fail to connect with WPA2.

And use a strong password, encryption is useless if you use an easy to guess or short password.

[roccenstein]

OK, I remembered how to access the router settings by typing that generic IP into the address window, but now what settings should I be looking for, which should I change, etc?

[Deerpark]

From what I can see in the manual there should be a section called wireless with a sub menu called security.
There you select the security mode. Here I suggest you try WPA 2 Personal first.
Then you select a WPA algorithm. I suggest you try AES first.
Then you enter a shared key also known as a password. You need to enter this password the first time a computer tries to access the network.
The last setting you don't need to touch.

If a device can't connect try selecting TKIP instead of AES. If it still doesn't work select WPA instead of WPA2. Hopefully your device support this mode. If not you will have to use WEP which is a far less secure encryption scheme.

[2k_dummy]

If you haven't already done so, be certain to change the default user name and password in routers setup. This is important

[roccenstein]

OK, I did all the things suggested, now how do I remove computers listed in the Linksys Easylink Advisor?  It gives me the option to add a new computer or other device, but no option for removing one that is already there.