Create a Configuration File for Yealink Phone

You can create a client file named "vpn.cnf" with a text editor (e.g. notepad++), or download a client.ovpn sample file.

Note: The line beginning with “;” is considered to disable the corresponding option.

Open the vpn.cnf file with a text editor.

Edit the following options according to the VPN server settings on your PBX.

Note: The client and server must use the same settings.

Specify the hostname/IP and port of VPN server.
In this example, we have forwarded the VPN server 10.8.0.1 1194 to 110.80.36.162 7086.
```
remote 110.80.36.162 7086
```
Set the protocol to UDP or TCP.
In this example, UDP is enabled while TCP is disabled.
```
proto udp
;proto tcp
```
Set the device mode to TAP or TUN.
In this example, TAP is enabled while TUN is disabled.
```
dev tap
;dev tun
```

Set the cryptographic cipher.

Table 1.
Cryptographic cipher on server	Cryptographic cipher on client
BlowFish	cipher BF-CBC
AES-128	cipher AES-128-CBC
AES-256	cipher AES-256-CBC
Triple-DES	cipher DES-EDE3-CBC

In this example, AES-256 is set on server, then you should enable AES-256-CBC on client.

;cipher BF-CBC
;cipher AES-128-CBC
cipher AES-256-CBC
;cipher DES-EDE3-CBC

If Compression is enabled on server, you need to enable compression on the VPN client.
```
comp-lzo
```
If Username/Password Authentication is used on server, you need to specify the pwd file.
```
auth-user-pass /config/openvpn/pwd
```
If SSL/TLS and a ta.key is used on the server, you need to specify the TLS Authentication & TA Key.
```
tls-auth ta.key 1
```
Specify the CA certificate file used on server.
```
ca /config/openvpn/keys/ca.crt
```

Specify the Yealink phone client certificate and key file.
In this example, Yealink.crt and Yealink.key is specified.
```
cert /config/openvpn/keys/Yealink.crt
key /config/openvpn/keys/Yealink.key
```

Edit other options according to your need.

persist-key
persist-tun
verb 3
resolv-retry infinite
remote-cert-tls server
nobind
;dev-node MyTap
;remote-random
;http-proxy-retry
;http-proxy [proxy server] [proxy port #]
;mute-replay-warnings
;mute 20

Save the client file.