So, a friend of mine was setting up a Linksys WRE54G Range Extender on her wireless network to eliminate a dead spot in her house.
She had issues with the Windows-based setup utility because it hardcodes the TCP/IP settings on the computer due to the fact it assumes that your network won’t be setup to work with the device out of the box. After that failed, and spending a while on the phone with a hapless Linksys tech support person, we finally got it configured via the web interface.
So everything is going fine until she notices that the MAC filter that was configured on the WRT54G was no longer effective.
It turns out that when you setup the WRE54G to work it invalidates the purpose of your MAC filtering. All traffic sent through the range extender is automatically flagged as OK.
From a Linksys forum post:
As a result, Wireless MAC Filtering on the main wireless router or access point will have no effect on clients connecting through a WRE54G Range Expander.
You have to wonder who makes the decisions on options with stuff like this. The Linksys tech I was chatting with online about this said that the best solution would be to enable WPA security, but their user guide for device specifically recommends doing MAC address filtering in addition to the encryption, except for the fact that you can’t.
Good game Linksys.