1 安装环境

Centos6.5

openvpn2.3.11

2 步骤

2.1 添加fedora的yum源

1	rpm -ivh http://mirrors.ustc.edu.cn/fedora/epel/6/x86_64/epel-release-6-8.noarch.rpm

2.2 安装openvpn

yum install openvpn -y

yum -y install openssl openssl-devel -y 

yum -y install lzo lzo-devel  -y 

yum install -y libgcrypt libgpg-error libgcrypt-devel

2.3 安装openvpn认证插件（LDAP认证使用）

1	yum install openvpn-auth-ldap -y

2.4 安装easy-rsa

由于openvpn2.3之后，在openvpn里面剔除了easy-rsa文件，所以需要单独安装

1
2
3

yum install easy-rsa
 
cp -rf /usr/share/easy-rsa/3.0.6 /etc/opevpn/easy-rsa

2.5 生成openvpn的key及证书

修改/opt/openvpn/etc/easy-rsa/2.0/vars参数

$ vi vars
export KEY_COUNTRY="CN"                 国家

export KEY_PROVINCE="ZJ"                省份

export KEY_CITY="NingBo"                城市

export KEY_ORG="TEST-VPN"               组织

exportKEY_EMAIL="81367070@qq.com"             邮件

export KEY_OU="baidu"                   单位

保存退出

2.5.1 创建服务器证书

./easyrsa clean-all 初始化目录，清理历史证书

./easyrsa build-ca 创建ca证书,设置ca证书密码，必须记着密码，为服务起名

./easyrsa gen-req server nopass 创建服务端证书，为server起名

./easyrsa sign server server 签约服务端证书，输入上面ca证书的密码

./easyrsa gen-dh 创建数据穿越密钥

2.5.2 创建客户端证书（使用客户端证书认证使用）

1
2
3

cd /etc/openvpn/client/
cp -rf /usr/share/easy-rsa/3.06 /etc/opevpn/client/
cd client/3.0.6

./easyrsa init-pki 初始化目录

./easyrsa build-ca 创建ca证书,记住密码，客户端登录要用

./easyrsa gen-req client1 创建客户端证书，输入客户端ca证书密码，也是客户端登陆密码

cd /etc/openvpn/easy-rsa/3.0.6
./easyrsa import-req /etc/openvpn/client/ 3.0.6/pki/reqs/client1.req client1 导入客户端证书

2.6 编辑openvpn服务端配置

2.6.1 拷贝配置文件

cd /etc/openpvn/easy-rsa/3.0.6/pki/
cp ca.crt /etc/openvpn/server/
cp private/server.key /etc/openvpn/server/
cp issued/server.crt /etc/openvpn/server/
cp dh.pem /etc/openvpn/server/
cp ca.crt /etc/openvpn/client/
cp issued/client1.crt /etc/openvpn/client/
cp /etc/openvpn/client/client/easyrsa3/pki/private/client1.key /etc/openvpn/client/

1 2	cd /etc/openvpn/server $ ls

1 2	cd /etc/openvpn/client $ ls

2.6.2 配置服务端配置文件

1	$ cat /etc/openvpn/server.conf

port 1194
proto tcp
dev tun
# 证书路径
ca keys/ca.crt
cert keys/server.crt
key keys/server.key  # This file should be kept secret
# 密钥路径
dh keys/dh.pem
server 10.8.0.0 255.255.255.0    //客户端分配的ip地址
push "route 172.20.17.0 255.255.255.0"  //推送客户端的路由
push "route 172.20.18.0 255.255.255.0"
push "route 172.20.19.0 255.255.255.0"
push "route 172.20.20.0 255.255.255.0"
push "route 172.20.22.0 255.255.255.0"
push "redirect-gateway"   //修改客户端的网关，使其直接走vpn流量，不配置走客户端流量
ifconfig-pool-persist ipp.txt    
keepalive 10 120
comp-lzo                //客户端和服务端保持一致
persist-key
persist-tun
status openvpn-status.log      //登录日志
verb 3
# LDAP认证插件，使用时配置
plugin /usr/lib64/openvpn/plugin/lib/openvpn-auth-ldap.so "/etc/openvpn/auth/ldap.conf" 
# 禁用客户端证书认证
client-cert-not-required
username-as-common-name 
log /var/log/openvpn.log

举例server.confLDAP方式配置文件

#################################################
# 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 a.b.c.d
# 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
proto tcp

# "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).
# 证书路径
ca /etc/openvpn/ca.crt 
cert /etc/openvpn/server.crt
key /etc/openvpn/server.key  # This file should be kept secret

# Diffie hellman parameters.
# Generate your own with:
#   openssl dhparam -out dh2048.pem 2048
# dh dh2048.pem
# 密钥路径
dh /etc/openvpn/dh.pem

# Network topology
# Should be subnet (addressing via IP)
# unless Windows clients v2.0.9 and lower have to
# be supported (then net30, i.e. a /30 per client)
# Defaults to net30 (not recommended)
;topology subnet

# 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 10.8.0.0 255.255.255.0

# 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"
# 发送路由
push "route 192.168.0.0 255.255.0.0"
# 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"

# 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"
# 设置发送的DNS
push "dhcp-option DNS 114.114.114.114"

# 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.
# 开启客户端互相访问
client-to-client

# 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.
# 心跳侦测
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 ta.key 0 # This file is secret

# Select a cryptographic cipher.
# This config item must be copied to
# the client config file as well.
# Note that v2.4 client/server will automatically
# negotiate AES-256-GCM in TLS mode.
# See also the ncp-cipher option in the manpage
# 加密方式
cipher AES-256-CBC

# Enable compression on the VPN link and push the
# option to the client (v2.4+ only, for earlier
# versions see below)
;compress lz4-v2
;push "compress lz4-v2"

# For compression compatible with older clients use comp-lzo
# If you enable it here, you must also
# enable it in the client config file.
# 和客户端保持一致
comp-lzo

# The maximum number of concurrently connected
# clients we want to allow.
;max-clients 100
# 最大连接数
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.
# 开启状态日志
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
# 日志路径
log /var/log/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 3

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

# Notify the client that when the server restarts so it
# can automatically reconnect.
# explicit-exit-notify 1

# LDAP认证
plugin /usr/lib64/openvpn/plugin/lib/openvpn-auth-ldap.so "/etc/openvpn/auth/ldap.conf"
# 关闭证书认证
client-cert-not-required

2.7 修改openvpn-ldap-auth的配置文件：

1	vi /etc/openvpn/auth/ldap.conf

<LDAP>
    # LDAP server URL
    #更改为AD服务器的ip
    URL     ldap://172.20.20.10:389               
 
    # Bind DN (If your LDAP server doesn't support anonymous binds)
    # BindDN        uid=Manager,ou=People,dc=example,dc=com
    #更改为域管理的dn,可以通过ldapsearch进行查询,-h的ip替换为服务器ip，-d换为管理员的dn，-b为基础的查询dn，*为所有
    #ldapsearch -LLL -x -h 172.16.76.238 -D "administrator@xx.com" -W -b "dc=xx,dc=com" "*"
    BindDN      " cn=administrator,cn=users,dc=dealeasy,dc=local" 
 
    # Bind Password
    # Password  SecretPassword
    #域管理员的密码
    Password    passwd
 
 
    # Network timeout (in seconds)
    Timeout     15
 
    # Enable Start TLS
    TLSEnable   no
 
    # Follow LDAP Referrals (anonymously)
    FollowReferrals no
 
    # TLS CA Certificate File
    #TLSCACertFile  /usr/local/etc/ssl/ca.pem
 
    # TLS CA Certificate Directory
    #TLSCACertDir   /etc/ssl/certs
 
    # Client Certificate and key
    # If TLS client authentication is required
    #TLSCertFile    /usr/local/etc/ssl/client-cert.pem
    #TLSKeyFile /usr/local/etc/ssl/client-key.pem
 
    # Cipher Suite
    # The defaults are usually fine here
    # TLSCipherSuite    ALL:!ADH:@STRENGTH
</LDAP>
 
<Authorization>
    # Base DN
    #查询认证的基础dn
    BaseDN      " ou=de,dc=dealeasy,dc=local"
 
    # User Search Filter
    #SearchFilter   "(&(uid=%u)(accountStatus=active))"
    #其中sAMAccountName=%u的意思是把sAMAccountName的字段取值为用户名，后面“memberof=CN=myvpn,DC=xx,DC=com”指向要认证的vpn用户组，这样任何用户使用vpn，只要加入这个组就好了
    SearchFilter    "( (&(sAMAccountName=%u)(memberof=cn=myvpn,ou=vpn,ou=de,DC=dealeasy,DC=local"
 
    # Require Group Membership
    RequireGroup    false
 
    # Add non-group members to a PF table (disabled)
    #PFTable    ips_vpn_users
 
    <Group>
        #BaseDN     "ou=Groups,dc=example,dc=com"
        #SearchFilter   "(|(cn=developers)(cn=artists))"
        #MemberAttribute    uniqueMember
        # Add group members to a PF table (disabled)
        #PFTable    ips_vpn_eng
        BaseDN      " ou=vpn,ou=de,dc=dealeasy,dc=local"
        SearchFilter    " (cn=myvpn)"
        MemberAttribute     "member"
    </Group>
</Authorization>

例子：openldap配置示例
使用了上面安装的openvpn-auth-ldap认证插件
client-cert-not-required不再需要客户端证书，将改为使用OpenLDAP中的用户认证
注意:上面的ldap.conf中RequireGroup true以及Group的配置实际我们期望是必须是LDAP中的名称为vpn的组下的用户才可以登录VPN。但根据这个ISSUE https://github.com/threerings/openvpn-auth-ldap/issues/7，当前2.0.3的openvpn-auth-ldap不支持。因此如果只想限制LDAP中某些用户可以使用VPN的话，只能设置`RequireGroup false，然后可以在SearchFilter中做一些文章，比如(&(uid=%u)(ou=vpn))`即只有用户的ou字段为vpn的才可以。

<LDAP>
	# LDAP server URL
	URL		ldap://192.168.0.129:389

	# Bind DN (If your LDAP server doesn't support anonymous binds)
	# BindDN		uid=Manager,ou=People,dc=example,dc=com
        BindDN      cn=admin,dc=zhjx,dc=com 
        Password *******
	# Bind Password
	# Password	SecretPassword

	# Network timeout (in seconds)
	Timeout		15

	# Enable Start TLS
	# TLSEnable	yes
        TLSEnable       no

	# Follow LDAP Referrals (anonymously)
	# FollowReferrals yes
        FollowReferrals   no

	# TLS CA Certificate File
	# TLSCACertFile	/usr/local/etc/ssl/ca.pem

	# TLS CA Certificate Directory
	# TLSCACertDir	/etc/ssl/certs

	# Client Certificate and key
	# If TLS client authentication is required
	#TLSCertFile	/usr/local/etc/ssl/client-cert.pem
	#TLSKeyFile	/usr/local/etc/ssl/client-key.pem

	# Cipher Suite
	# The defaults are usually fine here
	# TLSCipherSuite	ALL:!ADH:@STRENGTH
</LDAP>

<Authorization>
	# Base DN
	BaseDN		"ou=People,dc=zhjx,dc=com"

	# User Search Filter
	# SearchFilter	"(&(uid=%u)(accountStatus=active))"
        SearchFilter  "(uid=%u)"

	# Require Group Membership
	 RequireGroup	false
        #RequireGroup    true

	# Add non-group members to a PF table (disabled)
	#PFTable	ips_vpn_users

	<Group>
		BaseDN		"ou=Group,dc=zhjx,dc=com"
		SearchFilter	"cn=openvpn"
		MemberAttribute	memberUid
		# Add group members to a PF table (disabled)
		#PFTable	ips_vpn_eng
	</Group>
</Authorization>

2.8 拷贝/etc/openvpn/key目录下的ca.crt证书，以备客户端使用。

注：客户端使用ca.crt和客户端配置文件即可正常使用openvpn了

2.8.1 配置客户端配置文件

注意:
客户端ca证书使用的是和服务端一样的ca证书，都是创建服务端证书用到的ca文件

1	$ vi client.ovpn

client
dev tun
proto tcp                  //注意协议，跟服务器保持一致
remote 172.20.20.25 1194     //xx.xx.com替换为你的服务器ip
resolv-retry infinite
nobind
persist-key
persist-tun
ca ca.crt
auth-user-pass            //客户端使用账户密码登陆的选项，用于客户端弹出认证用户的窗口
comp-lzo
verb 3

例子：openldap方式客户端配置示例，与上方server版示例对照

##############################################
# 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.
# 服务端类型
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
# 与服务端一致
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.
# 与服务端一致
proto tcp
#proto udp

# The hostname/IP and port of the server.
# You can have multiple remote entries
# to load balance between the servers.
# 连接地址与端口
remote XXX.imwork.net 1194
#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.
# ldap方式只使用ca证书
ca ca.crt
# cert client.crt
# key client.key

# Verify server certificate by checking that the
# certicate has the correct key usage set.
# 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 keyUsage set to
#   digitalSignature, keyEncipherment
# and the extendedKeyUsage to
#   serverAuth
# EasyRSA can do this for you.
# remote-cert-tls server

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

# Select a cryptographic cipher.
# If the cipher option is used on the server
# then you must also specify it here.
# Note that v2.4 client/server will automatically
# negotiate AES-256-GCM in TLS mode.
# See also the ncp-cipher option in the manpage
# 与服务的保持一致
cipher AES-256-CBC

# Enable compression on the VPN link.
# Don't enable this unless it is also
# enabled in the server config file.
# 与服务的保持一致
comp-lzo

# Set log file verbosity.
verb 3

# Silence repeating messages
;mute 20


# auth-user-pass

# 开启账户密码认证
ns-cert-type server
auth-user-pass

2.9 开启路由转发

1	vi /etc/sysctl.conf

修改参数
net.ipv4.ip_forward = 1（默认为0，修改成1 表示开启路由转发，如果默认是空内容，请自行加上-腾讯云貌似就是空的）

重启sysctl生效路由转发：

sysctl -p

2.9.1 配置防火墙及路由转发策略：

iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE        #做NAT转换

iptables -A INPUT -p TCP --dport 1194 -j ACCEPT                                         #OpenVPN服务端口，可自定义，不可冲突

service iptables save

service iptables restart