On 26th April 2023, the judge ordered the temporary cessation of Telegram’s service in Brazil. This decision was forwarded to several Brazilian Internet Service Providers (ISPs).
Starting from 26th April 2023, several ISPs in Brazil started to block access to Telegram. Community members from Brazil shared OONI data on the block with their networks. Gustavo Gus from the Tor Project, for example, reported the blocking of Telegram in Brazil by sharing relevant OONI data on social media.
OONI has a specific Telegram test. The MAT chart clearly shows the onset of new blocking, and also shows that Telegram is not 100% blocked in every ISP.
The report goes on to analyze the results more finely and uncover some interesting details.
A per-ASN breakdown of the measurement coverage suggests that Telegram is not blocked on all tested networks in Brazil. OONI data, for example, shows that Telegram was reachable when tested on AS262374 on 28th April 2023, as the relevant measurements show that connections to the tested Telegram endpoints were successful.
What we can see from the above chart is that most networks block all endpoints starting from around 27th April 2023. In some cases, however, the provider did not block all the measured endpoints effectively, but only chose to block some of them. For example, on TIM S/A (AS26615), the four top endpoints are not blocked. Since we observe consistent IP blocking regardless of the port, it’s plausible to speculate that blocking depends on IP address rather than IP address and port. On Ligga Telecomunicações S.A. (AS14868), we observe different endpoints being accessible (from 7th to 10th April 2023 in the chart above). This leads us to believe that there is no information sharing amongst providers of the targets for the block and each provider chooses what to block autonomously. On Unifique Telecomunicações SA (AS28343), we observe no evidence of blocking at all.
By looking at the blocking time for a particular endpoint across providers, we can see how the time in which the blocking started varies from provider to provider.
As is evident through the above chart, TIM was the first provider to implement the block at around 23:00 UTC on 26th April 2023, followed by Telefônica Brasil an hour later, followed by Claro the following hour. Several hours later, at around 14:00 UTC on 27th April 2023, V tal (also known as Oi) started blocking Telegram, followed an hour later by Ligga.
OONI et al. have a new report analyzing the partial blocking of Telegram in Brazil starting this week.
https://ooni.org/post/2023-brazil-telegram/
OONI has a specific Telegram test. The MAT chart clearly shows the onset of new blocking, and also shows that Telegram is not 100% blocked in every ISP.
https://explorer.ooni.org/chart/mat?test_name=telegram&axis_x=measurement_start_day&since=2023-04-15&until=2023-05-01&time_grain=day&probe_cc=BR
The report goes on to analyze the results more finely and uncover some interesting details.