[tor-dev] Proposal 334: A flag to mark Relays as middle-only

Neel Chauhan neel at neelc.org
Sun Sep 12 19:21:18 UTC 2021

Hi nusenu,

On 2021-09-10 16:05, nusenu wrote:
> Thank you for working on this,
> I was hoping for such a flag for a long time,
> great to see that it is happening now.

No problem!

> The flag should minimize the ability of the relay to do harm.
> This means such relays should _not_ be used by tor clients for _any_
> other use-case than the second hop position (no HSDir, no fallbackdir, 
> ...).

My updated proposal (most recent s7r email) says a MiddleOnly relay is 
strictly a middle, and nothing else. The original did not say that, and 
I don't know if you got the original or the most recent.

> Also ensure this functionality is available to tor clients via a torrc 
> option
> like "ExcludeExitNodes" can be used by tor clients as well.
> The torrc option for clients could be named "LimitToMiddleOnlyNodes" or 
> similar
> and takes a list of relay fingerprints and can appear multiple times
> in a torrc (like ExcludeExitNodes).

I don't know if torrc options are supposed to go in Proposal documents, 
so I excluded it from there. I will try to make sure an 
"ExcludeMiddleNodes" option (how I would name it) would be included, 
although I may do it in another ticket/MR.

> If there are conflicting configurations the exclusion should overrule
> the inclusion of a relay fingerprint. Detected conflicts should cause
> a log entry.
> An example for a conflict:
> MapAddress, EntryNodes, ExitNodes (or any other including option)
> mentions a relay fingerprint that is also excluded.

Makes sense.

> kind regards,
> nusenu

No problem!


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