[tor-relays] Traffic in port 9050 in a relay (denial of service attack?)

Gordon Morehouse gordon at morehouse.me
Fri Nov 8 05:34:50 UTC 2013


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Lars Noodén:
> On 11/06/2013 01:26 PM, mick wrote:
>> I disagree. Dropping all traffic other than that which is 
>> explicitly required is IMHO a better practice. (And how do you
>> know in advance which ports get attacked?)
> 
> Using reject instead of drop simplifies troubleshooting.
> 
> http://www.chiark.greenend.org.uk/~peterb/network/drop-vs-reject
> 
> Drop tends to get in the way.

I agree with the above document, but on really low-end hardware (hi,
I'm the resident Raspberry Pi person ;)), and with consumer routers,
REJECT can also cause problems during a Tor SYN flood by consuming
resources on both the relay and the router.

Since I *do* agree with REJECTing when possible, I do a two-stage
approach and only DROP hosts which have proven themselves more
aggressive than I can deal with during an overload condition.  This
saves some resources to keep the relay alive.

Best,
- -Gordon M.


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