At home I have an insecure wireless network. A few weeks ago McAfee security asked whether I trust my network. Since I didn’t think that I have a network, I conducted some investigation and found Windows Vista was showing that several extra computers are appearing on the network. There is a hub using the IP address ending in .1 and three others ending in .2, .3, and (.2 is my own computer). I am unable to delete these computers. I will work on fixing the security issue once these computers are gone, but I cannot do any financial transactions until these are gone. In the meantime I do not trust my network and find that I get a message every few days about my computer not being secure. Can you help?

The reason that you are unable to delete these extra computers is that Windows Vista is simply detecting these computers being connected to your network. Before launching into a complete explanation of the problem, it would be worthwhile to conceptually explain how the network operates. From the description provided, your network is centred around a device called a router. All other devices (e.g. computers) on your network connect to the router, allowing them to communicate with each other and also the internet. As you can see, the router functions as a central point of control and rendezvous on the network. The reason that you cannot disconnect the extra computers from the network using Windows Vista is that Vista has no power or authority to disconnect these computers since these other computers are not directly connected to that computer, but are instead connected to the router. Therefore, you need to disconnect those computers at the router.

The fact that your router is insecure is a major security vulnerability which should be fixed as soon as possible, since this is allowing unauthorised parties the ability to connect into your network which is the most likely reason for the presence of the extra computers. Most people think that the only effect is that people can use your internet connection. While this is one of the major problems with having an insecure network, the other effect is that people can connect into your internet network and potentially spread viruses or attempt to access files and resources on computers which are connected on that network. Therefore, it is essential that security is implemented on the router to prevent this from occurring.

It is likely that your router is a wireless router, since other computers are connecting into your network without your knowledge. The only other way computers could be connecting is by using a network cable directly plugged into the router, which would not be feasible for a rogue user since they would need physical access to the router and it would also be fairly obvious if someone you don’t know is running a long cable from your router to their computer! Therefore, we will need to enable security on the wireless network.

In your question you mention that you will work on fixing the security issues once the rogue computers have gone. However, this is not normally the way we secure a router. It is possible to forcibly disconnect a computer from the router, but without implementing security the computer will be able to immediately reconnect to the network. Therefore, the best way to approach the securing of the router is to enable security. Enabling security on the router will mean that whenever someone wishes to connect onto your wireless network they will need to enter a passkey (which has been set by you) to connect. If they do not have the passkey then they will be unable to connect onto the network. Additionally, once you have enabled the passkey any computers which were connected onto the network will be disconnected until the passkey is entered. In the case of your authorised computers, you can just enter the passkey into the computers to immediately re-establish the connection. However, in the case of any other computers they will not be able to reconnect since they do not have the passkey.

Unfortunately I cannot provide specific guidance on how to enable security on your router, as each router is different and without the brand and model which you are using it will be difficult to give step-by-step instructions. However, from the provided information I can provide you with a starting point. Windows Vista has reported a “hub” device at the IP address ending with .1. This is likely to be your router (ignore that Vista is reporting the device as a hub). Open a web browser on your computer and then enter the IP address of the router and press ENTER. This should produce a login screen for the router. If you remember the username and password then enter these details. If you don’t know these details it is likely that they have never been changed from the defaults. The default username and password should be written on the bottom of the physical router, so try those credentials. If you find that those do not work, and you cannot access the router administration interface, then you will need to consult the manual for your router about doing a factory reset. This will reset all settings on the router, including the username and password, back to their defaults. You must be aware that this will also wipe all of your internet settings from the router, so make sure you have the settings from your ISP handy before embarking on this procedure so that they can be re-inputted into the router.

Assuming that you have gained access to the router there should be a section of the administration interface which refers to security or wireless security. If you are unsure, then refer to the manual which came with the wireless router. If you cannot find the manual then visit the website for the manufacturer of the device and you should be able to download the manual as a PDF document. Within the security section of the router you should be able to enable wireless security. It is likely that there are various options for the type of security to enable. You want to enable WPA-PSK. This is the enhanced security level (known as Wi-Fi Protected Access) using a pre-shared key. This means that you are configuring a pre-shared key on the router and this key needs to be entered into any computers which need to connect onto the wireless network. Once you select the WPA-PSK option you should be prompted to enter a pre-shared key. This is the passkey that you will need to enter on any computers that you wish to connect to the network. Type in a memorable passkey and then click the relevant button to save the settings. Once this has been done, any computers which were connected to the router via wireless should be disconnected and will only be able to reconnect after the passkey has been entered into those computers. Be aware, if the computer which you are using to enable security is connected via wireless then that machine will also be disconnected. In this instance, to re-establish the connection simply try reconnecting to the wireless network and enter the passkey when prompted.

That said, if your home computer is not connected to the router via wireless (but is instead connected using a network cable directly into the back of the router), and you do not have any wireless devices at all, then you may wish to consider disabling wireless on the router all together. As a matter of course, the more unnecessary services which you have enabled the more chance of someone managing to find a security flaw and a way into the system. You should always keep wireless security enabled, as this will mean that should you wish to enable wireless in the future then the security has already been setup, but disabling wireless when you are not using any wireless devices will also enable another layer of protection since this will mean to connect to the network people must use a network cable physically connected to the router, rather than a wireless signal. Within the wireless settings on the router there should be a setting which allows you to enable and disable the wireless radio on the device. Disable the wireless radio and then click the relevant button to save the settings. This setting change may require a restart of the router to take effect. Once the router has finished saving the setting change (and restarted, as required) wireless should be disabled on the router, providing that extra level of security. Should you wish to re-enable wireless in the future, simply re-enable the setting within the router administration page.

After you have followed the above procedures to configure and enable a wireless passkey on the router, and disabled wireless (if applicable), then Windows Vista should only show two devices connected to the network (i.e. the router, which Vista is calling a hub, and the computer which you are using). Be aware it may take Vista a few minutes to pick-up the changes to the network topology, but if the changes are not found after a few minutes, restart the computer which should force Vista to refresh the devices.