wget http://www.oberhumer.com/opensource/lzo/download/lzo-2.06.tar.gz
wget http://openvpn.net/release/openvpn-2.1.3.zip

yum install -y openssl openssl-devel automake pkgconfig iptables

tar zxvf lzo-2.06.tar.gz
cd lzo-2.06
make
make check
make install
cd ..

tar zxvf openvpn-2.1.3.tar.gz
cd openvpn-2.1.3
./configure --with-lzo-headers=/usr/local/include --with-lzo-lib=/usr/local/lib --with-ssl-headers=/usr/local/include/openssl --with-ssl-lib=/usr/local/lib
make
make install

cd easy-rsa/2.0/
vim vars
#调到最后找到一下代码
export KEY_COUNTRY="CN" #国家 CN就行
export KEY_PROVINCE="BJ" #省份
export KEY_CITY="BJ" #城市
export KEY_ORG="mosh" #组织
export KEY_EMAIL="wangshangyou@mosh.cn" #邮箱
export KEY_EMAIL=wangshangyou@mosh.cn #邮箱
export KEY_CN=changeme
export KEY_NAME=changeme
export KEY_OU=changeme
export PKCS11_MODULE_PATH=changeme
export PKCS11_PIN=1234
#保存退出

source vars

如果出现一下情况：
[root@li402-211 2.0]# source vars 
**************************************************************
  No /root/OpenVPN/openvpn-2.2.2/easy-rsa/2.0/openssl.cnf file could be found
  Further invocations will fail
*************************************************************
NOTE: If you run ./clean-all, I will be doing a rm -rf on /root/OpenVPN/openvpn-2.2.2/easy-rsa/2.0/keys

执行：
cp openssl-1.0.0.cnf openssl.cnf

./clean-all./build-ca

[root@li402-211 2.0]# ./build-ca 
Generating a 1024 bit RSA private key
................++++++
.........................++++++
writing new private key to 'ca.key'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [CN]:
State or Province Name (full name) [BJ]:
Locality Name (eg, city) [BJ]:
Organization Name (eg, company) [mosh]:
Organizational Unit Name (eg, section) [changeme]:mosh
Common Name (eg, your name or your server's hostname) [changeme]:v.wangshangyou.com
Name [changeme]:wsy
Email Address [wangshangyou@mosh.cn]:
[root@li402-211 2.0]#

./build-key-server server 

[root@li402-211 2.0]# ./build-key-server server
Generating a 1024 bit RSA private key

...++++++
....++++++
writing new private key to 'server.key'

-----

You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.

-----

Country Name (2 letter code) [CN]:
State or Province Name (full name) [BJ]:
Locality Name (eg, city) [BJ]:
Organization Name (eg, company) [mosh]:
Organizational Unit Name (eg, section) [changeme]:mosh
Common Name (eg, your name or your server's hostname) [server]:v.wangshangyou.com
Name [changeme]:wsy
Email Address [wangshangyou@mosh.cn]:


Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:mosh
Using configuration from /root/OpenVPN/openvpn-2.2.2/easy-rsa/2.0/openssl.cnf
Check that the request matches the signature
Signature ok
The Subject's Distinguished Name is as follows
countryName           :PRINTABLE:'CN'
stateOrProvinceName   :PRINTABLE:'BJ'
localityName          :PRINTABLE:'BJ'
organizationName      :PRINTABLE:'mosh'
organizationalUnitName:PRINTABLE:'mosh'
commonName            :PRINTABLE:'v.wangshangyou.com'
name                  :PRINTABLE:'wsy'
emailAddress          :IA5STRING:'wangshangyou@mosh.cn'
Certificate is to be certified until Mar  1 07:33:10 2022 GMT (3650 days)
Sign the certificate? [y/n]:y


1 out of 1 certificate requests certified, commit? [y/n]y
Write out database with 1 new entries
Data Base Updated
[root@li402-211 2.0]#

./build-key client1 #client1可以改名 但要以下面步骤一致  

[root@li402-211 2.0]# ./build-key wsy 
Generating a 1024 bit RSA private key
 ..++++++ 
...............++++++ 
writing new private key to 'wsy.key' 

----- 
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.

 ----- 

Country Name (2 letter code) [CN]: 
State or Province Name (full name) [BJ]: 
Locality Name (eg, city) [BJ]: 
Organization Name (eg, company) [mosh]: 
Organizational Unit Name (eg, section) [changeme]:mosh 
Common Name (eg, your name or your server's hostname) [wsy]:wsy 
Name [changeme]:wsy Email Address [wangshangyou@mosh.cn]: 
Please enter the following 'extra' attributes to be sent with your certificate request A challenge password []: 
An optional company name []:mosh 
Using configuration from /root/OpenVPN/openvpn-2.2.2/easy-rsa/2.0/openssl.cnf 
Check that the request matches the signature Signature ok The Subject's 
Distinguished Name is as follows countryName           
:PRINTABLE:'CN' stateOrProvinceName   
:PRINTABLE:'BJ' localityName          
:PRINTABLE:'BJ' organizationName      
:PRINTABLE:'mosh' organizationalUnitName
:PRINTABLE:'mosh' commonName            
:PRINTABLE:'wsy' name                  
:PRINTABLE:'wsy' emailAddress          
:IA5STRING:'wangshangyou@mosh.cn' 

Certificate is to be certified until Mar  1 07:39:00 2022 GMT (3650 days) 
Sign the certificate? [y/n]:y 

1 out of 1 certificate requests certified, commit? [y/n]y 

Write out database with 1 new entries Data Base Updated 
[root@li402-211 2.0]# 

./build-dh openvpn --genkey --secret keys/ta.key 

tar zcvf keys.tar.gz keys/ 
sz keys.tar.gz 

mkdir /etc/openvpn
mv keys.tar.gz /etc/openvpn/
cd ../../
cp sample-config-files/server.conf /etc/openvpn/
vim /etc/openvpn/server.conf

#################################################
# Sample OpenVPN 2.0 config file for            #
# multi-client server.                          #
#                                               #
# This file is for the server side              #
# of a many-clients <-> one-server              #
# OpenVPN configuration.                        #
#                                               #
# OpenVPN also supports                         #
# single-machine <-> single-machine             #
# configurations (See the Examples page         #
# on the web site for more info).               #
#                                               #
# This config should work on Windows            #
# or Linux/BSD systems.  Remember on            #
# Windows to quote pathnames and use            #
# double backslashes, e.g.:                     #
# "C:\\Program Files\\OpenVPN\\config\\foo.key" #
#                                               #
# Comments are preceded with '#' or ';'         #
#################################################

# Which local IP address should OpenVPN
# listen on? (optional)
local 106.182.53.211 #服务器外网ip

# Which TCP/UDP port should OpenVPN listen on?
# If you want to run multiple OpenVPN instances
# on the same machine, use a different port
# number for each one.  You will need to
# open up this port on your firewall.
port 1194

# TCP or UDP server?
proto tcp
;proto udp #走tcp协议

# "dev tun" will create a routed IP tunnel,
# "dev tap" will create an ethernet tunnel.
# Use "dev tap0" if you are ethernet bridging
# and have precreated a tap0 virtual interface
# and bridged it with your ethernet interface.
# If you want to control access policies
# over the VPN, you must create firewall
# rules for the the TUN/TAP interface.
# On non-Windows systems, you can give
# an explicit unit number, such as tun0.
# On Windows, use "dev-node" for this.
# On most systems, the VPN will not function
# unless you partially or fully disable
# the firewall for the TUN/TAP interface.
;dev tap
dev tun

# Windows needs the TAP-Win32 adapter name
# from the Network Connections panel if you
# have more than one.  On XP SP2 or higher,
# you may need to selectively disable the
# Windows firewall for the TAP adapter.
# Non-Windows systems usually don't need this.
;dev-node MyTap

# SSL/TLS root certificate (ca), certificate
# (cert), and private key (key).  Each client
# and the server must have their own cert and
# key file.  The server and all clients will
# use the same ca file.
#
# See the "easy-rsa" directory for a series
# of scripts for generating RSA certificates
# and private keys.  Remember to use
# a unique Common Name for the server
# and each of the client certificates.
#
# Any X509 key management system can be used.
# OpenVPN can also use a PKCS #12 formatted key file
# (see "pkcs12" directive in man page).
ca /etc/openvpn/keys/ca.crt
cert /etc/openvpn/keys/server.crt
key /etc/openvpn/keys/server.key  # This file should be kept secret

# Diffie hellman parameters.
# Generate your own with:
#   openssl dhparam -out dh1024.pem 1024
# Substitute 2048 for 1024 if you are using
# 2048 bit keys. 
dh /etc/openvpn/keys/dh1024.pem

# Configure server mode and supply a VPN subnet
# for OpenVPN to draw client addresses from.
# The server will take 10.8.0.1 for itself,
# the rest will be made available to clients.
# Each client will be able to reach the server
# on 10.8.0.1. Comment this line out if you are
# ethernet bridging. See the man page for more info.
server 192.168.10.0 255.255.255.0 #服务器分给客户端ip段

# Maintain a record of client <-> virtual IP address
# associations in this file.  If OpenVPN goes down or
# is restarted, reconnecting clients can be assigned
# the same virtual IP address from the pool that was
# previously assigned.
ifconfig-pool-persist ipp.txt

# Configure server mode for ethernet bridging.
# You must first use your OS's bridging capability
# to bridge the TAP interface with the ethernet
# NIC interface.  Then you must manually set the
# IP/netmask on the bridge interface, here we
# assume 10.8.0.4/255.255.255.0.  Finally we
# must set aside an IP range in this subnet
# (start=10.8.0.50 end=10.8.0.100) to allocate
# to connecting clients.  Leave this line commented
# out unless you are ethernet bridging.
;server-bridge 10.8.0.4 255.255.255.0 10.8.0.50 10.8.0.100

# Configure server mode for ethernet bridging
# using a DHCP-proxy, where clients talk
# to the OpenVPN server-side DHCP server
# to receive their IP address allocation
# and DNS server addresses.  You must first use
# your OS's bridging capability to bridge the TAP
# interface with the ethernet NIC interface.
# Note: this mode only works on clients (such as
# Windows), where the client-side TAP adapter is
# bound to a DHCP client.
;server-bridge

# Push routes to the client to allow it
# to reach other private subnets behind
# the server.  Remember that these
# private subnets will also need
# to know to route the OpenVPN client
# address pool (10.8.0.0/255.255.255.0)
# back to the OpenVPN server.
push "route 192.168.10.0 255.255.255.0"
;push "route 192.168.20.0 255.255.255.0"

# To assign specific IP addresses to specific
# clients or if a connecting client has a private
# subnet behind it that should also have VPN access,
# use the subdirectory "ccd" for client-specific
# configuration files (see man page for more info).

# EXAMPLE: Suppose the client
# having the certificate common name "Thelonious"
# also has a small subnet behind his connecting
# machine, such as 192.168.40.128/255.255.255.248.
# First, uncomment out these lines:
;client-config-dir ccd
;route 192.168.40.128 255.255.255.248
# Then create a file ccd/Thelonious with this line:
#   iroute 192.168.40.128 255.255.255.248
# This will allow Thelonious' private subnet to
# access the VPN.  This example will only work
# if you are routing, not bridging, i.e. you are
# using "dev tun" and "server" directives.

# EXAMPLE: Suppose you want to give
# Thelonious a fixed VPN IP address of 10.9.0.1.
# First uncomment out these lines:
;client-config-dir ccd
;route 10.9.0.0 255.255.255.252
# Then add this line to ccd/Thelonious:
#   ifconfig-push 10.9.0.1 10.9.0.2

# Suppose that you want to enable different
# firewall access policies for different groups
# of clients.  There are two methods:
# (1) Run multiple OpenVPN daemons, one for each
#     group, and firewall the TUN/TAP interface
#     for each group/daemon appropriately.
# (2) (Advanced) Create a script to dynamically
#     modify the firewall in response to access
#     from different clients.  See man
#     page for more info on learn-address script.
;learn-address ./script

# If enabled, this directive will configure
# all clients to redirect their default
# network gateway through the VPN, causing
# all IP traffic such as web browsing and
# and DNS lookups to go through the VPN
# (The OpenVPN server machine may need to NAT
# or bridge the TUN/TAP interface to the internet
# in order for this to work properly).
;push "redirect-gateway def1 bypass-dhcp"
push "redirect-gateway def1" #获取vpn服务器的默认网关

# Certain Windows-specific network settings
# can be pushed to clients, such as DNS
# or WINS server addresses.  CAVEAT:
# http://openvpn.net/faq.html#dhcpcaveats
# The addresses below refer to the public
# DNS servers provided by opendns.com.
;push "dhcp-option DNS 208.67.222.222"
;push "dhcp-option DNS 208.67.220.220"
push "dhcp-option DNS 106.187.35.20"
push "dhcp-option DNS 106.187.36.20"
push "dhcp-option DNS 106.187.34.20"

# Uncomment this directive to allow different
# clients to be able to "see" each other.
# By default, clients will only see the server.
# To force clients to only see the server, you
# will also need to appropriately firewall the
# server's TUN/TAP interface.
client-to-client #允许客户端相互访问

# Uncomment this directive if multiple clients
# might connect with the same certificate/key
# files or common names.  This is recommended
# only for testing purposes.  For production use,
# each client should have its own certificate/key
# pair.
#
# IF YOU HAVE NOT GENERATED INDIVIDUAL
# CERTIFICATE/KEY PAIRS FOR EACH CLIENT,
# EACH HAVING ITS OWN UNIQUE "COMMON NAME",
# UNCOMMENT THIS LINE OUT.
;duplicate-cn

# The keepalive directive causes ping-like
# messages to be sent back and forth over
# the link so that each side knows when
# the other side has gone down.
# Ping every 10 seconds, assume that remote
# peer is down if no ping received during
# a 120 second time period.
keepalive 10 120

# For extra security beyond that provided
# by SSL/TLS, create an "HMAC firewall"
# to help block DoS attacks and UDP port flooding.
#
# Generate with:
#   openvpn --genkey --secret ta.key
#
# The server and each client must have
# a copy of this key.
# The second parameter should be '0'
# on the server and '1' on the clients.
tls-auth /etc/openvpn/keys/ta.key 0 # This file is secret

# Select a cryptographic cipher.
# This config item must be copied to
# the client config file as well.
;cipher BF-CBC        # Blowfish (default)
;cipher AES-128-CBC   # AES
;cipher DES-EDE3-CBC  # Triple-DES

# Enable compression on the VPN link.
# If you enable it here, you must also
# enable it in the client config file.
comp-lzo

# The maximum number of concurrently connected
# clients we want to allow.
;max-clients 100

# It's a good idea to reduce the OpenVPN
# daemon's privileges after initialization.
#
# You can uncomment this out on
# non-Windows systems.
;user nobody
;group nobody

# The persist options will try to avoid
# accessing certain resources on restart
# that may no longer be accessible because
# of the privilege downgrade.
persist-key
persist-tun

# Output a short status file showing
# current connections, truncated
# and rewritten every minute.
status openvpn-status.log

# By default, log messages will go to the syslog (or
# on Windows, if running as a service, they will go to
# the "\Program Files\OpenVPN\log" directory).
# Use log or log-append to override this default.
# "log" will truncate the log file on OpenVPN startup,
# while "log-append" will append to it.  Use one
# or the other (but not both).
;log         openvpn.log
;log-append  openvpn.log

# Set the appropriate level of log
# file verbosity.
#
# 0 is silent, except for fatal errors
# 4 is reasonable for general usage
# 5 and 6 can help to debug connection problems
# 9 is extremely verbose
verb 4

# Silence repeating messages.  At most 20
# sequential messages of the same message
# category will be output to the log.
;mute 20

tar zxvf /etc/openvpn/keys.tar.gz
rm -rf /etc/openvpn/keys.tar.gz

cp sample-scripts/openvpn.init /etc/rc.d/init.d/openvpn
chkconfig --add openvpn

service openvpn restart

正常启动
[root@li402-211 openvpn-2.2.2]# service openvpn restart
Shutting down openvpn:                                     [  OK  ]
Starting openvpn:                                              [  OK  ]

chkconfig openvpn on

iptables -t nat -A POSTROUTING -s 192.168.10.0/24 -o eth0 -j SNAT --to-source 106.182.53.211
/etc/init.d/iptables save
/etc/init.d/iptables restart

sysctl -w net.ipv4.ip_forward=1

##############################################
# Sample client-side OpenVPN 2.0 config file #
# for connecting to multi-client server.     #
#                                            #
# This configuration can be used by multiple #
# clients, however each client should have   #
# its own cert and key files.                #
#                                            #
# On Windows, you might want to rename this  #
# file so it has a .ovpn extension           #
##############################################

# Specify that we are a client and that we
# will be pulling certain config file directives
# from the server.
client

# Use the same setting as you are using on
# the server.
# On most systems, the VPN will not function
# unless you partially or fully disable
# the firewall for the TUN/TAP interface.
;dev tap
dev tun

# Windows needs the TAP-Win32 adapter name
# from the Network Connections panel
# if you have more than one.  On XP SP2,
# you may need to disable the firewall
# for the TAP adapter.
;dev-node MyTap

# Are we connecting to a TCP or
# UDP server?  Use the same setting as
# on the server.
proto tcp
;proto udp #tcp协议

# The hostname/IP and port of the server.
# You can have multiple remote entries
# to load balance between the servers.
remote 106.182.53.211 1194 #服务器外网ip
;remote my-server-2 1194

# Choose a random host from the remote
# list for load-balancing.  Otherwise
# try hosts in the order specified.
;remote-random

# Keep trying indefinitely to resolve the
# host name of the OpenVPN server.  Very useful
# on machines which are not permanently connected
# to the internet such as laptops.
resolv-retry infinite

# Most clients don't need to bind to
# a specific local port number.
nobind

# Downgrade privileges after initialization (non-Windows only)
;user nobody
;group nobody

# Try to preserve some state across restarts.
persist-key
persist-tun

# If you are connecting through an
# HTTP proxy to reach the actual OpenVPN
# server, put the proxy server/IP and
# port number here.  See the man page
# if your proxy server requires
# authentication.
;http-proxy-retry # retry on connection failures
;http-proxy [proxy server] [proxy port #]

# Wireless networks often produce a lot
# of duplicate packets.  Set this flag
# to silence duplicate packet warnings.
;mute-replay-warnings

# SSL/TLS parms.
# See the server config file for more
# description.  It's best to use
# a separate .crt/.key file pair
# for each client.  A single ca
# file can be used for all clients.
ca keys/ca.crt
cert keys/wsy.crt
key keys/wsy.key

# Verify server certificate by checking
# that the certicate has the nsCertType
# field set to "server".  This is an
# important precaution to protect against
# a potential attack discussed here:
#  http://openvpn.net/howto.html#mitm
#
# To use this feature, you will need to generate
# your server certificates with the nsCertType
# field set to "server".  The build-key-server
# script in the easy-rsa folder will do this.
;ns-cert-type server

# If a tls-auth key is used on the server
# then every client must also have the key.
tls-auth keys/ta.key 1

# Select a cryptographic cipher.
# If the cipher option is used on the server
# then you must also specify it here.
;cipher x

# Enable compression on the VPN link.
# Don't enable this unless it is also
# enabled in the server config file.
comp-lzo

# Set log file verbosity.
verb 3

# Silence repeating messages
;mute 20


redirect-gateway def1 
route-method exe
route-delay 2