Firefox through Tor

Michael Holstein michael.holstein at
Thu Apr 27 18:31:32 UTC 2006

The problem (as I understand the question originally asked) was that 
regardless of TOR (or as you say, FoxyProxy, etc.) that sites can still 
'connect' you based on analysis of traffic from multiple time periods.

Eg: doubleclick .. sites A and B have a doubleclick ad. You get the 
doubleclick cookie (or likely already had it). They then realize that 
'bob at yahoo' is also the user that sent mail from 'anonymous at hotmail' 
since the same cookie was associated with your session from Yahoo (via 
doubleclick) and Hotmail (via doubleclick) -- even though you used TOR 
to access hotmail.

This is an application problem .. not a tor problem.

This problem is fixed if you close everything and dump cookies/cache 
before switching to/from TOR and direct-connection .. but there is one 
other case that I can think of..

Weatherbug. We used this once (former employer) to nail somebody that 
hacked a dialup account .. they had weatherbug running and didn't 
realize that once Weatherbug saw the Internet (and it uses the 
system-wide proxy values) it "called home", complete with the UID of the 
installation (which is unique to each installation, and in the URL the 
client requests). A quick examination of their PC matched the UID and 
bingo .. busted.



Eric H. Jung wrote:
> Hi Michael,
> Now that I understand I2P, perhaps you can respond to the rest of my email?
> The problem you identify does not seem to be any more or less exacerbated by FoxyProxy; the
> problem, if I understand correctly, exists regardless of whether not one uses FoxyProxy.
> So when you say "If you can't solve this problem automatically, you should be sure to
> warn users of these side-effects", I'm not sure why I should warn them. Can you explain further?
> Thank you,
> Eric Jung
> --- Michael Holstein <michael.holstein at> wrote:
>>>Forgive my ignorance. What is I2P?

More information about the tor-talk mailing list