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Re: Tor DNS lookups failing
Thus spake Jay Goodman Tamboli (jay@xxxxxxxxxx):
> A few months ago I modified Snakes on a Tor to do DNS lookups through
> various nodes and compare the results. At the time there was a node
> that was intermittently giving users an ad page instead of a real
> page. I found then that the only node that was returning an IP
> address that was incorrect was "whistlersmother," but I didn't report
> that here because I was a little unsure about my methodology.
> Last week I started scanning again with a better idea of what I was
> doing. Notably, the latest Tor alpha resets the DNS cache on NEWNYM,
> so I didn't have to much with the Tor source to stop it from caching
> the lookups. After a couple of days of scanning, I haven't found any
> nodes returning incorrect information, but I have seen more lookup
> failures than I remember seeing last time. This jibes with my
> personal experience, where I feel like I've seen more DNS lookup
> failures than previously.
> I was wondering, first, if other people are seeing fairly frequent
> erroneous DNS failures. Secondly, is there anything Tor can do to
> improve the situation, like requesting a second lookup via another
> circuit if one reports a failure, or maybe not caching failures? I'm
> not sure either of those is a good solution, but right now when I get
> a failure I have to either wait for the circuit to time out or send
> Tor NEWNYM. Otherwise the result seems to be cached, so a reload in
> my web browser just gives me the Privoxy error page again.
Yeah, I just started noticing a lot of DNS failures on my most recent
batch of scanning as well. I've got a fair amount of work to do before
SoaT 0.0.5 is ready (I think I've just about hit the limit of
maintainable complexity in a perl script :), but when it's done it
should be able to help us figure out which servers this is happening
at, as well as a shitload of other interesting info as well.
I'm hoping to make the release next weekend.
Mad Computer Scientist
fscked.org evil labs