Calls are flaky and SIP ALG is on the router.
SIP ALG on consumer routers rewrites SIP packets incorrectly, breaking registration or audio. Default advice from nearly every VoIP provider: turn SIP ALG off.
Try this first
- 1Open router admin and search for 'SIP ALG' or 'SIP helper'.
- 2Disable the option and reboot the router.
- 3Test registration and audio in both directions.
- 4On business routers, also enable NAT keepalive and consistent NAT binding to compensate.
When to bring us in
Consumer router will not let you disable SIP ALG: replace with a business model (MikroTik, Ubiquiti, Fortinet), that is not a luxury but a precondition for stable VoIP.
See also
- Voys, BelXS or RoutIT, which cloud PBX fits?Three popular NL platforms, differences are admin UI, partner model and per-user price.
- Teams Phone: Calling Plan, Direct Routing or Operator Connect?Three ways to connect PSTN to Teams, cost and management differ a lot.
- 3CX: self-host on VPS or take 3CX cloud?Self-host saves licence, but you own SBC, backup and updates.
None of the above fits?
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