Project: Make it harder to use exits as one-hop proxies

Proposal 163 outlined some ways to detect clients, and later emails elaborated on the issue, clarifying some parts and exposing hopeless muddiness in others.

There's an initial implementation of a variant of the concept in Tor now, under the RefuseUnknownExits configuration option. Unfortunately, turning it on seems to give many positives. We haven't investigated whether they're false positives or just jerks using Tor as a one-hop proxy.

Child Tickets: [[TicketQuery(parent=legacy/trac#1751 (moved))]]