这篇文章是OpenVPN的后续工作：Linux上的服务器设置。

我们将在另一台Debian Linux机器上安装并配置OpenVPN客户端，并将连接到之前创建的OpenVPN服务器。

安装OpenVPN客户端

在Debian上，OpenVPN客户端与服务器是相同的可执行文件。
因此，我们必须在客户端计算机上安装OpenVPN软件包：

# apt-get update && apt-get install openvpn

OpenVPN客户端配置

创建一个新目录来存储日志：

# mkdir /var/log/openvpn

将默认的“ client.conf”示例配置文件复制到“/etc/openvpn /”：

# cp /usr/share/doc/openvpn/examples/sample-config-files/client.conf /etc/openvpn

我们已经复制了Sandy的客户端密钥和在OpenVPN服务器配置期间创建的CA证书，并将它们放置在'/etc/openvpn'下：

# ls -1 /etc/openvpn/
ca.crt
client.conf
sandy.crt
sandy.key

剩下要做的就是修改配置文件，使其指向OpenVPN服务器。
打开并编辑客户端的配置文件，使其看起来类似于以下内容：

# cat /etc/openvpn/client.conf
#specify that we are a client
client
#using the same settings as we have on the server
dev tun
proto udp
#the hostname/IP and port of the server
remote openvpn.example.com 11194
#keep trying indefinitely to resolve the host name of the OpenVPN server
resolv-retry infinite
#most clients don't need to bind to a specific local port number
nobind
#downgrade privileges after initialisation (non-Windows only)
user nobody
group nogroup
#try to preserve some state across restarts
persist-key
persist-tun
#full paths to keys and certificates
ca /etc/openvpn/ca.crt
cert /etc/openvpn/sandy.crt
key /etc/openvpn/sandy.key
ns-cert-type server
#cryptographic cipher, must be the same on the server config file as well
cipher AES-256-CBC
#the same compression setting as we have on the server
comp-lzo
#log files
log /var/log/openvpn/openvpn.log
log-append /var/log/openvpn/openvpn.log
#log verbosity
verb 3

启动OpenVPN客户端

完成修改配置文件后，我们可以启动OpenVPN客户端服务：

# service openvpn start
[ ok ] Starting virtual private network daemon: client.

故障排除

检查以确保OpenVPN tun接口已启动：

# ifconfig tun
tun0  Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00

inet addr:10.26.0.6 P-t-P:10.26.0.5 Mask:255.255.255.255

UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1

RX packets:5948 errors:0 dropped:0 overruns:0 frame:0

TX packets:5948 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:100

RX bytes:499632 (487.9 KiB) TX bytes:499632 (487.9 KiB)

检查我们是否可以ping通OpenVPN服务器（在服务器上允许ping通）：

# ping -c 3 10.26.0.1
PING 10.26.0.1 (10.26.0.1) 56(84) bytes of data.
64 bytes from 10.26.0.1: icmp_req=1 ttl=64 time=0.165 ms
64 bytes from 10.26.0.1: icmp_req=2 ttl=64 time=0.103 ms
64 bytes from 10.26.0.1: icmp_req=3 ttl=64 time=0.116 ms
--- 10.26.0.1 ping statistics --
3 packets transmitted, 3 received, 0% packet loss, time 1999ms
rtt min/avg/max/mdev = 0.103/0.128/0.165/0.026 ms

路由表：

# netstat -nr
Kernel IP routing table
Destination  Gateway    Genmask

Flags MSS Window irtt  Iface
0.0.0.0

10.1.XY.1  0.0.0.0

UG

0 0

0     eth0
10.1.XY.0    0.0.0.0    255.255.255.0    U

0 0

0     eth0
10.26.0.1    10.26.0.5  255.255.255.255  UGH     0 0

0     tun0
10.26.0.5    0.0.0.0    255.255.255.255  UH

0 0

0     tun0