[tor-talk] variable speed limits on ports ...

[Robert Ransom]

On 2011-12-14, John Case <case at sdf.org> wrote:
>
> Let's say I run an exit node, and I have a 10 Mb/s connection.
>
> I join up, run for a while, get qualified as a good exit, speed checks out
> at 10, and so on.  All is well.
>
> But then let's say that, at the OS level, I rate limit one of the TCP
> ports I allow to exitto a much lower level - let's say I allow:
>
> 22,80,443,6667
>
> and 22,80,443 go full bore at 10 Mb/s, but I rate limit 6667 to 1 Mb/s.
>
> How does this get categorized by the Tor network ?  Do I continue to show
> as a 10 Mb/s exit node ?  Do I get labeled as a bad exit ?  Perhaps lots
> of exits do this and it is an accepted practice ?

I expect that no one would ever notice that per-port rate-limiting
configuration.

> I *think* the speed is tested via Tor network relay operations, and not on
> a per-exit-port basis, so I suspect as long as I keep my intra-Tor traffic
> running at 10, I get labeled as 10.  Correct ?

The ‘bandwidth authority’ currently measures exits' available
bandwidth by exiting to a test HTTPS server on port 443.  See
https://gitweb.torproject.org/torflow.git/blob/HEAD:/NetworkScanners/BwAuthority/README.spec.txt
for more information.


Robert Ransom