Public VoIP infrastructure is exposed by design. SIP, RTP, WebRTC, provisioning, and management services must remain reachable, but that does not mean every operational surface should be open to the internet.
MNSCloud treats security as a layered system. Linux hosts should have a clear firewall baseline, CrowdSec should analyze hostile behavior, agents should communicate outbound to the API, and service profiles should describe what needs protection without binding policy to a single PABX brand.
For FreeSWITCH, Asterisk, Kamailio, and OpenSIPS, the most important rule is simple: keep authority in the control plane. Public clients and installers can be open, auditable, and extensible, while tenant scope, secrets, billing, routing ownership, and policy decisions stay API-side.
That separation makes it possible to support customer-owned infrastructure without distributing private business logic or sensitive credentials.