I have a Linksys WRT54G router. 2 my laptops are running Windows XP Service Pack 2.
Router configured as follows
-SSID BROADCAST DISABLED
-WIRELESS MAC FILTER ENABLED
- Permit only PCs listed to access the wireless network (2 MACs entered)
- PASSWORD CHANGED

Despite all these configuration steps network considered as "UNSECURED WIRELESS NETWORK".
What to do to make it secure?
Thank you.
Eugene.

The reason it says that is because you are not using WEP, WPA, etc to secure the network. If there was a network key required then it would say "secured" if not, it says "unsecured". It does not detect that you have mac filtering, only that you have no network key.

Your network is just as secure with mac filtering(probably more) than using WEP.
If you'd like to test this, just remove one of your mac addresses then try to access the network.

If you still want to secure it using a network key, just look in the section for wireless security, you should find encryption settings. Just enter a WEP key using 64 or 128 bit HEX, I'd not suggest using ascii and you might want to stick to 64 bit if you are using cross branded hardware.

i would like to add one suggestion. since MAC addresses can be cloned( although unlikey) i would add WEP just to make sure you are that much more secure

Thanks to everybody for your support

Does WEP slow down the network performance? If so, by how much?

I did not notice any

I have read that it does, although I have been unable to reproduce that in real life. So it must be a very small amount if at all.

I have also read it depends on the router. I have seen claims of 30% performance degradation on some routers... It's all heresay though, so don't put too much stock in it.