At my office in the Penobscot Building, we have 3 computers (1 powerbook, 2 Windows) connecting through the net (DSL) through a Linksys router. We have restricted access through MAC address filtering to those devices and others, such as laptops, occasionally brought in, which has seemed fine without any WEP encryption ever since years ago when the Secret Service contacted us to tell us that our network had been used for nafarious activity by a war driver in the middle of the night (but that's another story). SSID is not broadcast.

Occasionally, our speed, which is restricted by DSL speed to about 2600 kb, crawls down to nothing. Late last Friday, it was down to 200 kb. Checking the active MAC address table, it showed five addresses on (in green), all on our allowed table, but only 3 computers were turned on. I turned off the other 2, leaving only my Powerbook, but still five showed active. I filtered out everything except my powerbook, and then only the one showed up and the connection went back up to 2600 kb.

The first thing that comes to mind is that someone is somehow spoofing our valid MAC addresses and joining the network, even though this would seem improbable in our large office building, and our broadcast signal from the router is weak. What else could it be? How do I check? And if I find out this is the case, is there some way I can track it down?

Aside from enabling encryption, is there anything else I can do. Also, how much does each form of encryption slow down speed?

quote:

Aside from enabling encryption, is there anything else I can do. Also, how much does each form of encryption slow down speed?

1. Make certain you router has the latest factory firmware.
2. Reset the router to factory defaults.
3. Re-configure the router using a different password (not in the dictionary).
4. Disable remote management access to the router.
5. Reset the MAC filtering to allow only known machines to connect.
6. Enable WPA shared key encryption.
7. Do not enable any incoming ports that are not absolutely necessary.

In my experience with Linksys wireless routers connecting both Macintosh and Windows systems, WPA is essentially cost-free and is certainly easily capable of 2.6 Mbps throughput. WPA certainly will not slow you down as much as theft of bandwidth!