Flexisip SIP Proxy on Ubuntu 24.04 LTS by cloudimg

Flexisip SIP Proxy on Ubuntu 24.04 LTS by cloudimg

Flexisip is Belledonne Communications' open source SIP proxy, registrar and presence server, the server behind Linphone. It routes SIP signalling, registers user agents, authenticates accounts and can act as a push notification gateway, providing the core of a self hosted VoIP and instant messaging platform. This cloudimg image installs the official bc-flexisip package from the Belledonne apt repository on Ubuntu 24.04 LTS under systemd as the unprivileged flexisip user, so it is dpkg managed and receives upstream security patches. Backed by 24/7 expert support.

Secure by default, no open relay

A SIP registrar that accepts unauthenticated registrations is an abuse and toll fraud magnet. This image enables Flexisip's authentication module with a file backed user database, so every REGISTER and INVITE for the served domain requires SIP digest authentication. There is no anonymous registration and no open relay. The image ships no fixed or known SIP credential: the single demo account has its secret generated per instance on the first boot of every VM, written to a root only file, and the proxy is held disabled until first boot has written the real secret and the resolved public IP SIP domain.

No toll fraud route

There is no PSTN gateway and no outbound trunk configured, so a compromised or unauthenticated endpoint cannot dial out. The media relay is disabled and presence, conference and back to back user agent servers are not enabled, so the appliance is a lean proxy and registrar that opens only SIP port 5060. The registrar datastore is a local Redis bound to loopback with no public port, so the appliance is fully standalone with no external service dependency.

Proven before capture

Every build proves a real SIP REGISTER round trip with the bundled sipexer client: a registration with the per instance secret returns 200 OK, a wrong secret is rejected, and an anonymous registration is refused. A fresh per instance secret is generated on every boot.

Ideal for

A self hosted SIP registrar and proxy, a VoIP account authentication front end, a Linphone or SIP softphone backend, a push notification gateway for mobile SIP clients, and a fully controlled open source alternative to hosted SIP providers.

Flexisip is licensed under the GNU Affero General Public License v3. The image ships the official upstream package unmodified. cloudimg is not affiliated with or endorsed by Belledonne Communications. Flexisip and Linphone are marks of Belledonne Communications and are used only to identify the software.