[tor-talk] Bursts of 'many circuit creation requests'

[Andreas Krey]

Hi all,

I'm occasionally seeing bursts of that in my log:

    Jul 08 08:37:59.000 [warn] Your computer is too slow to handle
    this many circuit creation requests! Please consider using the
    MaxAdvertisedBandwidth config option or choosing a more restricted
    exit policy.

I already have

  RelayBandwidthRate 50 KB  # Throttle traffic to 100KB/s (800Kbps)

and newly

  MaxAdvertisedBandwidth 40 KB

in my tor.rc but the latter did not help against these messages.
This is not an exit relay. (There are a few hidden services on
it whose .onions are not made public.)

This time I only stumbled over that because of how
the traffic on my DSL link looked:

  http://nr1.h.apk.li/traf-21600s-2012-07-08.png

Which is not the usual burst of tor traffic as incoming traffic is
more than twice the outgoing (red is total, not incoming).

I took a short tcpdump of the connection and noticed that there is
traffic from a number of high-bandwidth tor relays, not just one
single source.

I'd guess there is

 - either something running amok and trying to build circuits
   via a lot of different intermediate relays all through my node
   (or possibly other nodes as well; I can monitor only this one).

 - or this is done on purpose for some reason.

So, the question is: Is there something fishy or something buggy
going on here? Or neither, but then what is that?

Btw, does an non-exit relay only try to build circuits to known
other relays or can it be steered to other IP addresses/ports
by the circuit initiator?

There is also an old ticket on this topic:
https://trac.torproject.org/projects/tor/ticket/728

This is 0.2.3.12-alpha running on a pretty lowly AMD Geode 500 MHz.
I've taken the tor node offline for a few more hours.

Andreas

-- 
"Totally trivial. Famous last words."
From: Linus Torvalds <torvalds@*.org>
Date: Fri, 22 Jan 2010 07:29:21 -0800