Phonon
Your own phone system, closed to the public internet.
Phonon is a self-hosted phone system built on Asterisk. Phones register only through a private WireGuard tunnel, calls are encrypted with SRTP, and a SIP trunk such as Twilio connects your number to the public phone network.
Public SIP scanners are blocked; only tunnel members can register.
SRTP media encryption inside the tunnel.
Inbound and outbound calls through a SIP trunk.
Works with apps such as Linphone on iOS and Android.
How it is set up
Connect a number
Create a SIP trunk with your provider and attach your phone number.
Generate configuration
Phonon generates the PBX, dial plan and firewall configuration.
Deploy
One installer brings up the PBX, the WireGuard tunnel and a firewall that only allows the provider's signaling networks.
Onboard phones
Scan a QR code to join the tunnel, then sign in with the softphone app.
Why it is hard to attack
Invisible to scanners
The public SIP ports are closed. Only WireGuard (UDP 51820) and your SIP trunk provider's signaling networks are allowed through the firewall, which removes SIP scanning, password guessing and toll fraud.
Encrypted twice
Signaling and media travel inside the WireGuard tunnel, and calls are also encrypted with SRTP.
Checked, not assumed
A health check confirms the public SIP ports are closed and validates the tunnel keys and subnet.
Calls that still ring
Phones keep the tunnel alive so incoming calls reach a locked phone instead of going to voicemail.
Included
- Voicemail (dial *97).
- Automatic formatting of outbound numbers to the E.164 format your trunk expects.
- SIP trunks from Twilio or VoIP.ms.
- Softphone profiles for Linphone and Zoiper on iOS, Android and desktop, with a QR code to join the tunnel.
- Health checks for the PBX and the trunk.
Try Phonon with your own data
See the sample demo first, then tell us about your environment. We agree the scope with you before anything is installed.