Onsite Proxy

Overview

The Onsite Proxy is a command-line proxy software that creates a secure connection between your Cloud PBX and IP phones deployed at remote locations. It overcomes common firewall and networking issues by acting as a local relay between the phones and the cloud-based PBX.

To manage Onsite Proxy instances, log in to the PBX admin portal and navigate to System > Onsite Proxy.

Scenario

When multiple IP phones are deployed in a remote subnet (e.g., a branch office), you can install the Onsite Proxy on a host in the same subnet as those phones. Only the proxy needs a connection to the cloud PBX—the individual phones do not need direct access to the cloud.

The onsite proxy then forwards provisioning links, SIP signaling, and RTP packets between the phones and the PBX, making them work as if they were on the same network as the PBX. This eliminates the need to configure port forwarding or firewall rules for each phone individually and reduces latency compared to traditional remote access solutions.

Key features

Auto-discovery of IP phones

The Onsite Proxy automatically discovers available IP phones on the same subnet via PnP (Plug and Play) and reports their information (including MAC address, IP address, vendor, and model) to the PBX.

Zero-touch auto provisioning

When you assign extensions to IP phones discovered by the onsite proxy, the proxy automatically pushes the provisioning link from the PBX to the phones. The phones then download their configuration and complete extension registration without manual intervention.

Proxy SIP signaling

The onsite proxy forwards SIP registration requests from phones to the PBX and maintains a stable registration. It relays all SIP signaling (such as REGISTER, INVITE, and BYE) between the phones and the PBX over a single UDP port 5060 on the proxy host.

Audio RTP Passthrough

The onsite proxy supports audio RTP passthrough. When enabled, if IP phones are registered via the same Onsite Proxy, the RTP audio streams between them are transmitted directly (peer-to-peer), bypassing both the PBX and the proxy. This reduces latency, saves bandwidth, and improves call quality.

Requirements

Onsite Proxy host

Recommended specifications

The capacity supported by the Onsite Proxy depends on the system resources allocated to the host.

Step 1. Add an onsite proxy instance on the PBX

Before installing the Onsite Proxy software, you need to create an Onsite Proxy instance on the PBX. This generates the connection credentials (connection address, UUID, and secret key) that you will need during the proxy installation.

1. Log in to the PBX admin portal and go to System > Onsite Proxy, then click Add.

2. In the Basic section, configure the following settings:

   Setting	Description
   Name	Enter a name to identify this onsite proxy instance (e.g., the branch office location).
   Platform	Select Linux.

   

3. In the Audio RTP Passthrough section, enable or disable the option as required.
   • If enabled, RTP audio streams between phones registered via the same Onsite Proxy are transmitted directly (peer-to-peer).
   • If disabled, RTP audio streams are relayed by the PBX.
4. Click Save and Apply.

The Onsite Proxy instance appears in the list with its automatically generated connection information (connection address, UUID, and secret key).

Step 2. Install the Onsite Proxy software

Install the Onsite Proxy on a Linux host in the same subnet as the IP phones. During installation, a configuration wizard guides you through connecting the proxy to the Cloud PBX.

Prerequisites

• You have added an Onsite Proxy instance on the PBX (Step 1) and obtained the connection credentials (connection address, UUID, secret key).
• The Linux host meets the requirements listed above (operating system, port, IP address).
• HTTPS must be enabled for the PBX connection address.

Download and extract the installation package

1. Access the command line on the Onsite Proxy host.
2. Run sudo -i to switch to the root user.
3. Download the latest Onsite Proxy installation package:
   • x86_64:
     wget https://www.virtual-call.net/hubfs/download/onsite-proxy/onsiteproxy-x86_64.tar.gz -O /tmp/onsiteproxy.tar.gz
   • ARM64:
     wget https://www.virtual-call.net/hubfs/download/onsite-proxy/onsiteproxy-aarch64.tar.gz -O /tmp/onsiteproxy.tar.gz
4. Extract the package to the root directory:
   tar -xzf /tmp/onsiteproxy.tar.gz -C /

Run the installer and configure the connection

1. Run onsite-proxy-install to start the installation.

2. In the Onsite Proxy Installation window, verify the version and system details, then select Yes and press Enter.

   

3. In the Important Requirements window, confirm that UDP port 5060 is available and HTTPS is enabled, then press Enter.

   

4. In the Configuration Wizard welcome window, press Enter to begin.

   

5. Configure the connection information from the PBX:

   Setting	Description
   PBX Connection Address	Paste the connection address obtained from the PBX. This can be an IP address or a domain name.
   UUID	Paste the UUID obtained from the PBX.
   Secret Key	Paste the secret key obtained from the PBX. Keep this key secure and do not share it.
   PBX External Web Server Port	The HTTPS port of the PBX. For the Cloud PBX, the default is 443.
   PBX External Tunnel Port	The tunnel port used for the proxy connection. Default: 1090.
   Local IP	Select the static IP address assigned to the proxy host, or choose manual to enter it manually.

   

6. In the Configuration Summary window, verify all settings and select Yes to confirm.

   

7. Wait for the verification to complete. In the Verification Successful and Configuration Complete windows, press Enter to continue.

   

8. In the Installation Complete window, press Enter to finish.

   

The onsite proxy is now installed and connected to the Cloud PBX. On the PBX, the instance status changes to a green checkmark, showing the proxy version, internal IP address, and public IP address.

Manage Onsite Proxy

View status and information

Go to System > Onsite Proxy to view the status of all Onsite Proxy instances. The list shows the name, platform, version, UUID, and secret key for each instance. You can also use the search field and column filter to find specific instances.

Edit an Onsite Proxy instance

Click the edit icon next to an instance to change its name, platform, or audio RTP passthrough setting. The Connection Information section also displays the connection address, UUID, and secret key.

Query proxy status and information

After the onsite proxy is connected, you can view detailed status information by clicking the status icon next to the instance. This includes the proxy version, internal and public IP addresses, and system resource utilization.

Reconfigure or uninstall the proxy

After installation, you can use the following commands on the proxy host: