Printer Not Found: MAC Address Filtering Strikes Again

[#1]

The last posting talked about discovery and how it can be blocked by a firewall. This can also happen with a wireless printer, but another common problem with wireless printers is MAC address filtering.

It is surprising to see how many people try to MAC address filtering as a security feature when it actually creates problems without improving security of a wireless network. Here are a couple of other articles that mention MAC address filtering that you can find on the web:

HP Article – Getting Started with Wireless Networking

“Mac Address Filtering: It is assumed these measures will increase security, but this isn't true. Enabling Mac address filtering and disabling broadcasting of the network name will make the setup and use of the wireless network more difficult.”

http://www.hp.com/united-states/consumer/digital_photography/print_better_photos/tips/wireless.html 

Blog – The Six Dumbest Ways to Secure a Wireless LAN

 “MAC filtering takes the most effort to manage with zero ROI (return on investment) in terms of security”

http://blogs.zdnet.com/Ou/index.php?p=43

One reason that MAC address filtering so problematic is that it is a non-standard feature. By "non-standard”, I mean that it is not part of the 802.11 standards. Because it is non-standard, there is no way to tell a client that they are being blocked because of MAC address filtering. Instead, the router tells the client that it has successfully joined the network but then just completely ignores the client. (How rude!)  A typical user will think that they have successfully configured the printer to be on their wireless network, but nothing will work. By the way, most HP wireless inkjets have the ability to detect when it thinks it is being blocked by MAC address filtering. Although the router does not inform the printer of MAC address filtering, if the printer is told it has successfully joined the wireless network but then doesn’t hear anything more from the router, then a good guess is that MAC address filtering is the reason why. Look in your wireless printer documentation to see if it can print a wireless network test report; this will indicate if the printer thinks it is being blocked by MAC address filtering.

We seen MAC address filtering frequently when looking at customer problems with wireless printers. Often they did not set up the network themselves, so they had no idea that MAC address filtering was enabled, or that such a thing even existed. Or they set up the network a long time ago and just forgot about it. Whatever the reason, it happens frequently and customers are often surprised by it. So be sure to check for this, and think long and hard before setting up MAC address filtering if you set up a wireless network for a friend; are you really doing them a favor or just creating a problem for them?

[#2]

And what do you do if the Wireless Network Test Report says to temporarily disable MAC address filtering to configure the printer, but MAC address filtering isn't enabled?

[#3]

MAC address filtering is a "guess" that the printer makes when it has associated with the wireless network but does not detect any network traffic. There are some other router settings which I've seen cause this to happen, such as the printer being set up as being the DMZ for the network, but this is pretty rare. If the printer doesn't seem to be working and the test report says it thinks the problem is MAC address filtering, I'd look at router settings to see if something is excluding the printer from the network, something other than wireless settings (SSID, encryption key).

[#4]

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[#5]

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[#6]

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