[tor-dev] Why is my bridge not publishing statistics?

David Fifield david at bamsoftware.com
Fri May 5 23:30:52 UTC 2017

I searched for the Snowflake bridge in Atlas, and couldn't find it. Its
fingerprint is 2B280B23E1107BB62ABFC40DDCC8824814F80A72. Its torrc is
stock "Last updated 9 October 2013 for Tor" except for
these settings:
	ContactInfo David Fifield <dcf at torproject.org>
	SOCKSPort 0
	ORPort 9001
	BridgeRelay 1
	ExtORPort auto
	ServerTransportPlugin snowflake exec /usr/local/bin/snowflake-server --acme-hostnames snowflake.bamsoftware.com --acme-email dcf at torproject.org --log /var/log/tor/snowflake-server.log
	ServerTransportListenAddr snowflake

Its ORPort 9001 is blocked by the local firewall, because it is meant to
be only a Snowflake bridge, and not a vanilla bridge. (Most of the
default Tor Browser obfs4 bridges are configured the same way, with
their ORPort blocked.) There are these messages in the log (which I
	[warn] Your server ( has not managed to confirm that its ORPort is reachable. Please check your firewalls, ports, address, /etc/hosts file, etc.

Why is the bridge not appearing in Atlas? I initially suspected
https://bugs.torproject.org/18050, whose changelog entry is:
	- Check that both the ORPort and DirPort (if present) are reachable
	  before publishing a relay descriptor. Otherwise, relays publish a
	  descriptor with DirPort 0 when the DirPort reachability test takes
	  longer than the ORPort reachability test.
	  Closes bug #18050. Reported by "starlight", patch by "teor".
	  Bugfix on, commit a1f1fa6ab on 27 Feb 2005.
But if it's the case that an unreachable ORPort causes descriptors not
to be uploaded, then why do the default obfs4 bridges appear in Atlas?
For example:
Actually, now that I look at it, I notice some other default bridges are
not present in Atlas, for example the two from
https://bugs.torproject.org/21917, which went out in Tor Browser 6.5.2:

What's going on and how can we fix it? You can find a list of default
bridge fingerprints here:

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