Re: Multiple WLAN Routers with same SSID

[Bjørn Mork <bjorn mork no>]

Larry Finger <Larry Finger lwfinger net> writes:
> On 09/21/2012 12:14 PM, Marius Kotsbak wrote:
>>
>> On Sep 20, 2012 11:38 PM, "Petric Frank" <pfrank gmx de <mailto:pfrank gmx de>>
>> wrote:
>>  > In fact (here in Germany) german telecom delivered WLAN-routers which all have
>>  > preset the same (E)SSID. Shall i go to every household (even if i can locate
>>  > them) in my environment to tell them to change their SSID ?
>>
>> That is bad (but it seems like Linksys routers are the same), but you should be
>> able to change the SSID of the AP you use.
>
> As far as I know, all routers from a given manufacturer come from the
> factory with the same ESSID and the same router password.

Not necessarily.  But I'd like to share a little horror story of why the
alternative isn't necessarily any better...

Many years ago, the ISP I work for decided that we wanted a unique ESSID
and password on every CPE we send out to our customers.  So we made that
a vendor requirement.  No problem. Several vendors could deliver that.
But "unique" does not equal "random".  The vendor did of course use some
algorithm to come up with the ESSIDs and passwords, and the result
should not surprise anyone.  It took me one two-word Google search to
come up with this as hit #3:
http://www.gredil.net/WPAkeyCalc/KeyCalculator.html

One could of course argue that the end users were no worse off than if
they had received CPEs with the same ESSID and password, but the fact is
that they were.  The uniqueness gave a warm and fuzzy "secure" feeling,
making fewer users change it from default.

And then someone combined wardriving data with calulator output and
published long lists of coordinates, essid and password.  This did not
look good in media.  And it was decided that we had to fix it.  But how?
We do manage the CPEs and can change any setting.  But you cannot just
change the wireless settings for an end user.  How are they going to
connect then?  You have to change every device connected to their home
network as well.

We ended up redirecting them to a web portal, providing information
about the problem and some guidance on what to do.  And not letting them
access the Internet again until they have selected a new ESSID and
password and at least have reconfigured the device they use to access
the portal.  Hassle for us, and lots of hassle for the end users.  And
to avoid overloading support, we have to limit the rate to a few
thousand users a day.  Which means this will take forever.

Unique ESSIDs definitely was not worth the trouble.  But we have learned
a lot while trying to fix the bummer.



Bjørn