Help: How to authenticate additional attribute

Garber, Neal Neal.Garber at
Sun Oct 15 17:33:38 CEST 2006

> when the radius server authenticates the user, or whenever it is
re-associated again to the AP, 
> it will prompt the user to enter the password and location

This may prove difficult if you are using the std. Windows supplicant
since it

caches credentials.  We use WinXP with PEAP/MS-Chapv2 and I don't get

reprompted for a password when it reauthenticates.  I believe Vista has
the capability

to NOT cache wireless credentials.  You perhaps could also have
something delete the

reg. key where the credentials are stored - that would force it to
prompt again..  Perhaps

you are using another supplicant that won't have this issue and that you
could modify

to prompt for additional information (loc.coord.)..??  Also, if location
coordinates are

generally known (10,10 = bldg 10/office 10 and 100,100 equals bldg 100,
office 100),

then how do you prevent users from entering the wrong coordinates in
order to bypass

your check?  Even if your scheme isn't as simple as I described above,
if the location coord.

of a place is constant, over time people will learn the coordinates and
they won't be

useful as an additional security check.  Are these numbers randomly

or does each set of coordinates statically refer to a specific location
(that's what I meant

when I was asking the meaning of the coordinates)?  If they're random,
how will the

information be given to the users?  

> Thereafter, the radius server will check on the password and the
location coordinate. 
> If either is not right, it will reject the connection. 

> The server will maintain a set of legitimate location coordinates in a

> and it will be updated by another program automatically. 


Well, assuming you have a way to prompt, capture and send the "location

in the radius request, I would use rlm_perl during authorize and have it
compare the

location coordinate attribute to data in the file.  You can easily
return RLM_REJECT if the

user hasn't specified a valid location coordinate.  If you are planning
to bury the information

inside another attribute, you should check out attr_rewrite and hints as
they have the

ability to modify/create request attributes.  As a caveat, this may not
be the best approach

though as I have only been using FR for a short time.


> In the future, the coordinate may be derived by a system.


If you're trying to authorize by physical location, have you thought
about controlling

to which AP's they are authorized to connect (e.g., by Huntgroup-Name or

NAS-IP-Address)?  Also, Cisco AP's have a "dot11 location" config.

that could be used to automatically pass static information as part of

radius requests (each AP would always pass the same static info though

the config. was changed). If this would work for you, the user wouldn't
need to

enter anything (and they couldn't spoof the location coordinates).


Does this help you?

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