[tor-dev] Connections failed to default obfs4 bridges

[Rob Jansen]

> On Mar 28, 2018, at 12:23 PM, David Fifield <david at bamsoftware.com> wrote:
> 
> On Wed, Mar 28, 2018 at 10:57:13AM -0400, Rob Jansen wrote:
>> In a recent connectivity test to the default obfs4 bridges [0], we found that we are unable to connect to 10 or so of them (from open networks, i.e., no local filtering).
>> 
>> Is this a feature, like some of them only respond to users in certain parts of the world? Or is this a bug, like the default list of bridges refers to old bridges that are no longer available? Or am I misunderstanding functionality here?
> 
> Do you mean 10 distinct IP addresses, or 10 ports on a few IP addresses?
> Not all the IP addresses in the list are distinct.
> 

Turns out this was 10 ports on the same IP address. And we did the measurements back in December, so they are already a bit dated.

> Even while Lynn Tsai, Qi Zhong, and I were closely monitoring default
> bridge reachability, a lot of the default bridges were often offline,
> because of reboots, iptables problems, etc. See for example the "Orbot
> bridges" strip of Figure 5.2 here; the gray and red areas that precede
> blocking are where the bridge was simply offline:
> https://www.bamsoftware.com/papers/thesis/fifield-thesis.pdf#page=43
> 
> We have a lot of past measurements of default bridges. The rows with
> site="eecs-login" are from the U.S.
> https://www.bamsoftware.com/proxy-probe/ (download the repo, not
> probe.csv.gz, which isn't as recent)

Ahh, this is great, thanks for sending!

Best,
Rob
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: Message signed with OpenPGP
URL: <http://lists.torproject.org/pipermail/tor-dev/attachments/20180328/402ade9c/attachment.sig>