[anti-censorship-team] cdn.sstatic.net sometimes resolves to Cloudflare, since 2023-09-20 14:00

[David Fifield]

I made a graph of the bandwidth on the two bridges since this started
happening.

The two vertical lines mark:
2023-09-20 14:00:00	earliest known case of domain resolving to Cloudflare
2023-09-21 18:00:00	change to foursquare.com in rdsys
			https://gitlab.torproject.org/tpo/anti-censorship/rdsys-admin/-/merge_requests/17

1. snowflake-02 bandwidth has dwindled to almost nothing. Seriously
   almost nothing: it's around 3 MB/s currently.
2. There's a huge almost instantaneous step in snowflake-01 at around
   2023-09-21 13:00:00. At first, I thought this might have been a
   consequence of the rdsys change, but it's about 5 hours earlier than
   that. What could it be? Some unrelated unblocking event that just
   happened to happen while this domain stuff is happening?

On Wed, Sep 20, 2023 at 01:03:06PM -0600, David Fifield wrote:
> According to OONI measurements, the domain cdn.sstatic.net has started
> sometimes to resolve to a Cloudflare IP address, rather than a Fastly
> one. If a Snowflake client gets a Cloudflare IP address, their
> connection will fail, with this in the tor log:
> 
> [notice] Managed proxy "./client": offer created
> [notice] Managed proxy "./client": broker failure Unexpected error, no answer.
> 
> OONI has measurements of cdn.sstatic.net. The earliest measurement that
> resolved to a Cloudflare IP address is timestamped 2023-09-20 13:58:50:
> 
> https://explorer.ooni.org/m/20230920135923.824819_SE_webconnectivity_68a1a7b4e669dd2e
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