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[tor-talk] Tor is out

Tor introduces a new approach to providing fallback
directory mirrors for more robust bootstrapping; fixes more issues where
clients with changing network conditions refuse to make any circuits;
adds initial support for exiting to IPv6 addresses; resumes being able
to update our GeoIP database, and includes the geoip6 file this time;
turns off the client-side DNS cache by default due to privacy risks;
and fixes a variety of other issues.


Packages will come later (it's an alpha after all).

Changes in version - 2012-12-24
  o Major features (client resilience):
    - Add a new "FallbackDir" torrc option to use when we can't use
      a directory mirror from the consensus (either because we lack a
      consensus, or because they're all down). Currently, all authorities
      are fallbacks by default, and there are no other default fallbacks,
      but that will change. This option will allow us to give clients a
      longer list of servers to try to get a consensus from when first
      connecting to the Tor network, and thereby reduce load on the
      directory authorities. Implements proposal 206, "Preconfigured
      directory sources for bootstrapping". We also removed the old
      "FallbackNetworkstatus" option, since we never got it working well
      enough to use it. Closes bug 572.
    - If we have no circuits open, use a relaxed timeout (the
      95-percentile cutoff) until a circuit succeeds. This heuristic
      should allow Tor to succeed at building circuits even when the
      network connection drastically changes. Should help with bug 3443.

  o Major features (IPv6):
    - Tor now has (alpha) support for exiting to IPv6 addresses. To
      enable it as an exit node, make sure that you have IPv6
      connectivity, then set the IPv6Exit flag to 1. Also make sure your
      exit policy reads as you would like: the address * applies to all
      address families, whereas *4 is IPv4 address only, and *6 is IPv6
      addresses only. On the client side, you'll need to wait until the
      authorities have upgraded, wait for enough exits to support IPv6,
      apply the "IPv6Traffic" flag to a SocksPort, and use Socks5. Closes
      ticket 5547, implements proposal 117 as revised in proposal 208.

      We DO NOT recommend that clients with actual anonymity needs start
      using IPv6 over Tor yet, since not enough exits support it yet.

  o Major features (geoip database):
    - Maxmind began labelling Tor relays as being in country "A1",
      which breaks by-country node selection inside Tor. Now we use a
      script to replace "A1" ("Anonymous Proxy") entries in our geoip
      file with real country codes. This script fixes about 90% of "A1"
      entries automatically and uses manual country code assignments to
      fix the remaining 10%. See src/config/README.geoip for details.
      Fixes bug 6266. Also update to the December 5 2012 Maxmind GeoLite
      Country database, as modified above.

  o Major bugfixes (client-side DNS):
    - Turn off the client-side DNS cache by default. Updating and using
      the DNS cache is now configurable on a per-client-port
      level. SOCKSPort, DNSPort, etc lines may now contain
      {No,}Cache{IPv4,IPv6,}DNS lines to indicate that we shouldn't
      cache these types of DNS answers when we receive them from an
      exit node in response to an application request on this port, and
      {No,}UseCached{IPv4,IPv6,DNS} lines to indicate that if we have
      cached DNS answers of these types, we shouldn't use them. It's
      potentially risky to use cached DNS answers at the client, since
      doing so can indicate to one exit what answers we've gotten
      for DNS lookups in the past. With IPv6, this becomes especially
      problematic. Using cached DNS answers for requests on the same
      circuit would present less linkability risk, since all traffic
      on a circuit is already linkable, but it would also provide
      little performance benefit: the exit node caches DNS replies
      too. Implements a simplified version of Proposal 205. Implements
      ticket 7570.

  o Major bugfixes (other):
    - Alter circuit build timeout measurement to start at the point
      where we begin the CREATE/CREATE_FAST step (as opposed to circuit
      initialization). This should make our timeout measurements more
      uniform. Previously, we were sometimes including ORconn setup time
      in our circuit build time measurements. Should resolve bug 3443.
    - Fix an assertion that could trigger in hibernate_go_dormant() when
      closing an or_connection_t: call channel_mark_for_close() rather
      than connection_mark_for_close(). Fixes bug 7267. Bugfix on
    - Include the geoip6 IPv6 GeoIP database in the tarball. Fixes bug
      7655; bugfix on

  o Minor features:
    - Add a new torrc option "ServerTransportListenAddr" to let bridge
      operators select the address where their pluggable transports will
      listen for connections. Resolves ticket 7013.
    - Allow an optional $ before the node identity digest in the
      controller command GETINFO ns/id/<identity>, for consistency with
      md/id/<identity> and desc/id/<identity>. Resolves ticket 7059.
    - Log packaged cell fullness as part of the heartbeat message.
      Diagnosis to try to determine the extent of bug 7743.

  o Minor features (IPv6):
    - AutomapHostsOnResolve now supports IPv6 addresses. By default, we
      prefer to hand out virtual IPv6 addresses, since there are more of
      them and we can't run out. To override this behavior and make IPv4
      addresses preferred, set NoPreferIPv6Automap on whatever SOCKSPort
      or DNSPort you're using for resolving. Implements ticket 7571.
    - AutomapHostsOnResolve responses are now randomized, to avoid
      annoying situations where Tor is restarted and applications
      connect to the wrong addresses.
    - Never try more than 1000 times to pick a new virtual address when
      AutomapHostsOnResolve is set. That's good enough so long as we
      aren't close to handing out our entire virtual address space;
      if you're getting there, it's best to switch to IPv6 virtual
      addresses anyway.

  o Minor bugfixes:
    - The ADDRMAP command can no longer generate an ill-formed error
      code on a failed MAPADDRESS. It now says "internal" rather than
      an English sentence fragment with spaces in the middle. Bugfix on
    - Fix log messages and comments to avoid saying "GMT" when we mean
      "UTC". Fixes bug 6113.
    - Compile on win64 using mingw64. Fixes bug 7260; patches from
    - Fix a crash when debugging unit tests on Windows: deallocate a
      shared library with FreeLibrary, not CloseHandle. Fixes bug 7306;
      bugfix on Reported by "ultramage".

  o Renamed options:
    - The DirServer option is now DirAuthority, for consistency with
      current naming patterns. You can still use the old DirServer form.

  o Code simplification and refactoring:
    - Move the client-side address-map/virtual-address/DNS-cache code
      out of connection_edge.c into a new addressmap.c module.
    - Remove unused code for parsing v1 directories and "running routers"
      documents. Fixes bug 6887.

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