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Phone-Calling Server
(alien.top)
A place to share alternatives to popular online services that can be self-hosted without giving up privacy or locking you into a service you don't control.
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We welcome posts that include suggestions for good self-hosted alternatives to popular online services, how they are better, or how they give back control of your data. Also include hints and tips for less technical readers.
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You are looking for VOIP.
Asterisk is the main goto, but it is still waiting for patches to some RCE vulns disclosed last DEFCON.
Your country might not support using a mobile number with VOIP providers, mine does though.
Good luck.