WP820 OpenVPN Guide

  • Updated on March 11, 2022

VPN (Virtual Private Network) is a network that communicates by creating a dedicated and encrypted network channel (tunnel) on the public network, which can help remote users, company branches, business partners and suppliers in practical applications. Establish a secure and trusted network connection between them.

Figure 1: VPN Architecture Overview

OpenVPN® is a well-known open source VPN software, very stable and reliable to use, its main features: open source, cross-platform, easy to use, stable and secure. The WP820 can be used as a client to connect to a VPN server using the OpenVPN® function for remote communication. This article briefly describes how the WP820 uses the OpenVPN® feature.


If users want to use the OpenVPN function, they need to set the OpenVPN related configuration from the WP820 Web GUI as follow:

  1. Log in to the WP820 Web GUI page.
  2. Navigate to Network Settings 🡪 OpenVPN® Settings page.
  3. Check Enable OpenVPN®.
  4. Select either Simple Mode or Expert Mode, Then Configure related parameters or upload a configuration file to save the configuration.


The WP820 supports two modes:

  • Simple Mode: only configure some basic or common parameter configurations.
  • Expert Mode: support configuration file upload, fully customized.

After switching modes, the phone needs to be restarted for the new settings to take effect.

Simple Mode

Figure 2: OpenVPN® Settings Page – Simple Mode



Enable OpenVPN®

This enables/disables OpenVPN® functionality and requires the user to have access to an OpenVPN® server.


To use OpenVPN® functionalities, users must enable OpenVPN® and configure all of the settings related to OpenVPN®, including server address, port, OpenVPN® CA, certificate and key. Additionally, the user must also set the SIP account to use "OpenVPN" for the "NAT Traversal" under Account -> General Settings -> Network Settings

OpenVPN® Mode

Select either Simple Mode (Default) or Expert Mode.

Enable OpenVPN® Comp-lzo

Choose to enable/disable the LZO compression. When the LZO Compression is enabled on the OpenVPN server, you must turn on it at the same time. Otherwise, the network will fail to connect.

OpenVPN® server address

The URL/IP address for the OpenVPN® server.

OpenVPN® port

Set up the network port to communicate with the OpenVPN® server. The default port is 1194.

OpenVPN® Transport

Determines network protocol used for OpenVPN® (UDP or TCP). The default setting is TCP.


The OpenVPN® certificate used for authentication with OpenVPN® servers. Click "Upload" to upload the certificate file (ca.crt) to the device.

OpenVPN® client certificate

The OpenVPN® Client Certificate used for authentication with OpenVPN® servers. Click "Upload" to upload the client certificate file (*.crt) to the device.

OpenVPN® client key

The OpenVPN® client key used for authentication with the OpenVPN® server. Click "Upload" to upload the client certificate file (*.key) to the device.

OpenVPN® Cipher Method

Set the OpenVPN® encryption method, you must use the same encryption method as the OpenVPN® server. Supported encryption methods are Blowfish, AES-128 and AES-256.

OpenVPN® username

Set the OpenVPN® username (optional).

OpenVPN® password

Set the OpenVPN® password (optional).

Professional Mode (Expert Mode)

Professional mode supports configuration file upload in zipped format, which is totally customized by need, please refer to https://openvpn.net for more information.

Figure 3: OpenVPN® Settings Page – Expert Mode

The below example shows the Professional mode (Expert Mode) related configuration:

  1. Select OpenVPN mode as Expert Mode,
  2. Click “upload zip file” and browse your local directory to select the custom configuration file.

  • A zip format file is required for the upload feature.
  • The zip file must contain the “client.conf” and a certificate file (.crt)
  • The zip file should contain the files as shown in below screenshot:

Figure 4: Expert Mode ZIP file

The contents of the client.conf file format are as follows:

# Indicates that the file is a client configuration file
# The tun mode is used. Currently OpenVPN® only supports this mode.
dev tun
# Connection method used
proto udp
#VPN Service address
remote 1194
# Connection failed number of attempts
connect-retry 3

# Whether to bind local address and port

# Indicates whether the server push routing configuration 
# When the attribute is not configured, the custom route and server push route will take effect.
# If this attribute is configured, the custom route and server push route will not take effect.

# Indicates whether to redirect all traffic to OpenVPN as shown below to indicate that ipv4 is redirected to OpenVPN
# Can use “!” to express the opposite
# Configurable value ipv4 ipv6. If not configured, the default is redirect all traffic to OpenVPN.
redirect-gateway !ipv4 ipv6

# Configuring custom routes

# Configure account and password
# The first parameter is the account name
# The second is the account password
;auth -user -pass Account Passwd 

# Certificate configuration path. The configuration file needs to be an absolute file path.
ca /data/openvpn/ca.crt
cert /data/openvpn/client1.crt
key /data/openvpn/client1.key

# Specify DNS resolution retry interval
resolv-retry infinite

# Configuring DNS. Generally using DNS delivered by the VPN server
dhcp-option DNS

# Transmission encryption
cipher BF-CBC
# Whether to enable the lzo compression algorithm and other OpenVPN custom features

# Specify the server verification method.
ns-cert-type server
# Debugging log level 
verb 3

*OpenVPN is a registered trademark of OpenVPN Inc

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