Wow. I have been listening to the “Security Now” podcast for several weeks, and this evening listened to their episode from October 28th on “WEP and MAC Address Filtering.”

I had been under the rather strong conviction that wireless home users were silly to enable encryption, which did serve to keep some folks off their network, but also slowed down connections so much that it made the security step not worthwhile. I thought there were better ways to keep non-hacker neighbors off your wireless network that would not slow down all wireless connections to the Internet. My recommendation to others had been to:

1- Change the default name of the wireless network
2- Disable the broadcast SSID (so others can’t easily see and browse to your network)
3- If more security is needed, enable MAC address filtering. (MAC doesn’t refer to “Macintosh” here, we are talking about the unique ID number assigned to the network card being used)

The latter step is an “affirmative” security procedure, where you individually authorize different computers to access your wireless network.

What I learned on the Security Now podcast episode is that all these steps may be effective to keep casual users from jumping onto your home wireless network, but they won’t keep someone with basic tools off it. The reason is that packet sniffer software can see your wireless network even if the SSID is hidden. This defeats steps 1 and 2 above. And as far as MAC filtering goes, the opening salvo of packets sent by a computer accessing a network (wireless or otherwise) contains its MAC address. So again, anyone with a packet sniffer can easily find out the MAC address of an authorized computer accessing the network, and then use that address (spoof its own using the authenticated one) to gain access to the network.

I also learned why WEP encryption is pretty much worthless, as far as keeping determined folks out of your wireless network, and why users should go with WPA encryption instead.

Sadly, for my own network, I can get my wireless device to log into the wireless router when WPA encryption is turned on, but it won’t pick up a good, functional, local IP address. It just gets a self-assigned one. I am using a Linksys router and did upgrade the firmware tonight to the latest version, tried this with the broadcast SSID turned on, with MAC address filtering turned off, but still no dice.

So, now I know my wireless network is really not secure, and the “Security 101 for Teachers” article I wrote sometime back is pretty misleading / incorrect with the advice provided about home wireless configurations. The advice is still OK, in that it will probably keep most people from browsing onto your wireless network. But if anyone is serious about getting onto your network and has a packet sniffer (and someone determined to do something illegal online is probably more likely to) then these precautionary steps are pretty much worthless. So if you are trying to limit access to your own home wireless network by following the above steps– then you basically aren’t doing anything (without WPA encryption) that is likely to stop a determined hacker.

I will probably spend more time later working on getting my WPA encryption to work at home. For now I am giving up. But at least I am better informed! Clearly these security settings ARE pretty complicated. Not hard to understand why so many people just plug in their wireless routers and don’t bother with any type of encryption. The liability concerns of doing this should dissuade most if not all from doing this– if someone else is doing something illegal by hopping onto your wireless network, the liability could potentially come back to you (the homeowner and payer of the Internet access bill) if the RIAA or someone else comes knocking….

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