Mysteries of Telegram Data Centers

2 hours ago

Telegram has 5 data centers (DC1-5) with specific geographic locations; DC5 in Singapore is known for frequent downtime, especially affecting Chinese users with +86 phone numbers.
DC allocation is based on phone number country code at registration: DC1 (USA, +1), DC2 (Germany, +49), DC4 (Netherlands, European numbers), DC5 (Singapore, +86). DC3 has no current users, having likely migrated to DC1.
Three methods to determine user DC: Login method via MTProto error, Profile picture/file method using dc_id field, and Web CDN method (which misidentifies DC2/3 as DC4/1 due to shared domains). Bots using Web CDN may be inaccurate.
Testing confirms DC3 no longer accepts new users, with existing users transferred to DC1. Users can choose DC by phone number country code to avoid issues like DC5 downtime.

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