Firewall Wizards: RE: Wireless

["Carl Friedberg" <friedberg () exs esb com>]

Paul,

An easy starting point (very easy to use, and very low cost) is to buy an Orinoco Gold card, put it in a laptop, and 
get netstumbler (www.netstumbler.org).

It's not an enterprise solution, but for a quick heads up, it's a very impressive piece of software.

I've found that the el-cheapo stuff (Linksys and SMC, haven't used any D-Link but suspect it comes from the same, or 
similar manufacturer) just is not reliable enough. Especially when you turn on encryption, (128-bit Wep) I've found 
that those routers tend to stop forwarding packets after some random amount of time, requiring a reboot. The RF 
characeristics are not as good as Orinoco (or, presumably, Cisco Aironet).

If you can afford it, go with Cisco. They have some excellent white papers (as usual) describing the Cisco add-ons 
which will make it much harder to get rogue ap's and/or PC Cards connecting to your network. They use techniques like 
rekeying with every packet, etc. Cisco is working on various techniques which integrate this to an enterprise, 
including Radius, etc.

Some noteworthy points about WiFi:

(1) all forms of WEP have been cracked; and the software to do that is easily available;

(2) WiFi is radio, so 802.11a has higher bandwidth and shorter range than 802.11b. 802.11b can/will interfer with other 
devices on the same frequence band, such as newer portable phones, some microwaves, and potentially (though they deny 
it) Blue Tooth.

(3) WiFi uses half duplex, so it is a shared collision domain, just like the old days of 10mbps and hubs. The more 
users on an AP, the less bandwidth each can get.

(4) Any allowed access points should be on their own subnet, and in their own security domain.

(5) Most illicit installations have "out of the box" settings, typically the password, ip settings, and lack of 
encryption. That makes it easy to take control of the rogue AP and potentially completely disable it (i.e., change 
admin password and IPrange, disable wireless, disable DHCP, etc).

(6) WiFi is radio. You could get fancy and try to triangulate to find out where it is, but that is getting more 
expensive.

my 2 cents

Carl

-----Original Message-----
From: Paul Robertson [mailto:proberts () patriot net]
Sent: Friday, August 09, 2002 2:03 PM
To: firewall-wizards () honor icsalabs com
Subject: [fw-wiz] Wireless


How are people starting to deal with hunting down and killing rogue 
Wireless Access Points (WAPs)[1]?  It seems pretty easy in environments 
where wireless isn't allowed at all, but is anyone dealing with the situation in 
an environment where there are sanctioned wireless networks?

Thanks,

Paul
[1] I'm thinking a lot about the built-in laptop WAPs, people bringing in 
802.11b-enabled hubs, and only slightly about the cleaning folks hiding 
one in the ceiling tiles.
-----------------------------------------------------------------------------
Paul D. Robertson      "My statements in this message are personal opinions
proberts () patriot net      which may have no basis whatsoever in fact."
probertson () trusecure com Director of Risk Assessment TruSecure Corporation


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