@TOC

一、服务端安装配置(Linux)

1. 安装openvpn [root@slave1 ~]# yum install -y epel-release [root@slave1 ~]# yum install -y install openvpn easy-rsa net-tools bridge-utils

   [root@slave1 ~]# yum install -y epel-release
   ......
   Complete!
   [root@slave1 ~]# yum install  -y install openvpn easy-rsa net-tools bridge-utils
   ......
   Complete!

2. 创建PKI证书和CA证书 ！注意: 创建CA证书时输入的密码，后续会用上 [root@slave1 ]# cd /usr/share/easy-rsa/3 [root@slave1 3]# ./easyrsa init-pki [root@slave1 3]#./easyrsa build-ca

   [root@slave1 openvpn-2.4.8]# cd /usr/share/easy-rsa/3
   [root@slave1 3]# ./easyrsa init-pki 
   init-pki complete; you may now create a CA or requests.
   Your newly created PKI dir is: /usr/share/easy-rsa/3/pki
   
   [root@slave1 3]# ./easyrsa build-ca
   
   Using SSL: openssl OpenSSL 1.0.2k-fips  26 Jan 2017
   
   Enter New CA Key Passphrase:                # 设定密码，后面签约证书时需要
   Re-Enter New CA Key Passphrase:             # 确认密码
   Generating RSA private key, 2048 bit long modulus
   ....+++
   ......+++
   e is 65537 (0x10001)
   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.
   -----
   Common Name (eg: your user, host, or server name) [Easy-RSA CA]:ZCREATE_VPN # 自定义名称
   
   CA creation complete and you may now import and sign cert requests.
   Your new CA certificate file for publishing is at:
   /usr/share/easy-rsa/3/pki/ca.crt

3. 创建服务器证书和客户端证书 [root@slave1 3]# ./easyrsa build-server-full server1 nopass [root@slave1 3]# ./easyrsa build-client-full client1 nopass

   [root@slave1 3]# ./easyrsa build-server-full server1 nopass
   
   Using SSL: openssl OpenSSL 1.0.2k-fips  26 Jan 2017
   Generating a 2048 bit RSA private key
   .+++
   .......................+++
   writing new private key to '/usr/share/easy-rsa/3/pki/private/server1.key.jYEjOIedC6'
   -----
   Using configuration from /usr/share/easy-rsa/3/pki/safessl-easyrsa.cnf
   Enter pass phrase for /usr/share/easy-rsa/3/pki/private/ca.key:  #输入创建CA证书时的密码
   Check that the request matches the signature
   Signature ok
   The Subject’s Distinguished Name is as follows
   commonName            :ASN.1 12:'server1'    #服务器证书名称
   Certificate is to be certified until Jan 20 17:06:08 2023 GMT (1080 days)
   
   Write out database with 1 new entries
   Data Base Updated
   
   [root@slave1 3]# ./easyrsa build-client-full client1 nopass
   
   Using SSL: openssl OpenSSL 1.0.2k-fips  26 Jan 2017
   Generating a 2048 bit RSA private key
   ................................................+++
   ................................................................+++
   writing new private key to '/usr/share/easy-rsa/3/pki/private/client1.key.LB0gwbDPAA'
   -----
   Using configuration from /usr/share/easy-rsa/3/pki/safessl-easyrsa.cnf
   Enter pass phrase for /usr/share/easy-rsa/3/pki/private/ca.key: #输入创建CA证书时的密码
   Check that the request matches the signature
   Signature ok
   The Subject’s Distinguished Name is as follows
   commonName            :ASN.1 12:'client1'   #客户端证书名称
   Certificate is to be certified until Jan 20 17:19:56 2023 GMT (1080 days)
   
   Write out database with 1 new entries
   Data Base Updated

4. 生成创建Diffie-Hellman，确保key穿越不安全网络的命令; 创建TLS-Auth Key [root@slave1 3]# ./easyrsa gen-dh [root@slave1 3]# openvpn --genkey --secret ./pki/ta.key

   [root@slave1 3]# ./easyrsa gen-dh
   
   Using SSL: openssl OpenSSL 1.0.2k-fips  26 Jan 2017
   Generating DH parameters, 2048 bit long safe prime, generator 2
   This is going to take a long time
   ....................................................................................................................................................................................................................................................................................................................................................................+.................+........................................+....................................................................+............................................................................................................................+...........................................................................+........................................................................................................................................................................................................................................................................................................................+......................+..................................................................................+...................................................................................+.......................+..........+................................................................+............................+...........+....................................................................................................................................................................................................................++*++*
   
   DH parameters of size 2048 created at /usr/share/easy-rsa/3/pki/dh.pem
   
   [root@slave1 3]# openvpn --genkey --secret ./pki/ta.key 

5. 配置OpenVPN Server 将证书秘钥拷贝至/etc/openvpn/server/的issued与private中 [root@slave1 3]# cp -pR /usr/share/easy-rsa/3/pki/{issued,private,ca.crt,dh.pem,ta.key} /etc/openvpn/server/ 拷贝配置文件模板并编辑 [root@slave1 3]# cp /usr/share/doc/openvpn-2.4.8/sample/sample-config-files/server.conf /etc/openvpn/server/ [root@slave1 3]# vim /etc/openvpn/server/server.conf

   [root@slave1 3]# cp -pR /usr/share/easy-rsa/3/pki/{issued,private,ca.crt,dh.pem,ta.key} /etc/openvpn/server/  
   [root@slave1 3]# cp /usr/share/doc/openvpn-2.4.8/sample/sample-config-files/server.conf /etc/openvpn/server/
   [root@slave1 3]# vim /etc/openvpn/server/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)
   # OpenVPN服务器本地地址
   local 10.1.30.100
   
   # 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.
   # OpenVPN服务器端口
   port 1194
   
   # TCP or UDP server?
   ;proto tcp
   proto udp
   
   # "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.
   # 申明使用的设备可选tap基于桥接模式和tun基于路由模式，tap是二层设备，支持链路层协议。
   ;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
   # 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证书，client1的证书和密钥
   ca ca.crt
   cert issued/server1.crt
   key private/server1.key
   # cert server.crt
   # key server.key  # This file should be kept secret
   
   # Diffie hellman parameters.
   # Generate your own with:
   #   openssl dhparam -out dh2048.pem 2048
   ;dh dh2048.pem
   dh 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.
   # 指定OpenVPN子网地址（自己根据规划分配）
   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.
   # 自定义向客户端推送路由，需注释push "redirect-gateway def1 bypass-dhcp"
   push "route 10.1.0.0 255.255.0.0"
   # 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).
   # 向客户端push网关,自定义push "route 后需注释此行
   ;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.
   # 向客户端push 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.
   # 让客户端彼此可以互相访问
   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.
   # 定义openvpn一个证书在同一时刻是否允许多个客户端接入，默认没有启用
   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.
   # 心跳检测
   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.
   # 此处客户端配置文件中该参数需要改为 1
   key-direction  0
   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
   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
   # For compression compatible with older clients use comp-lzo
   # 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.
   # 并发连接最大数量，非必须，默认注释
   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.
   # 状态文件
   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).
   # 记录日志，每次重新启动openvpn后删除原有的log信息。也可以自定义log的位置。默认是在/etc/openvpn/目录下
   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
   # 日志级别
   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

6. 启动openvpn-server服务并设置开机自启动 [root@slave1 server]# systemctl start openvpn-server@server [root@slave1 server]# systemctl enable openvpn-server@server

   [root@slave1 server]#  systemctl start openvpn-server@server 
   [root@slave1 server]# systemctl enable openvpn-server@server
   Created symlink from /etc/systemd/system/multi-user.target.wants/[email protected] to /usr/lib/systemd/system/[email protected].

7. 关闭linux安全子系统，关闭防火墙 [root@slave1 ~]# vim /etc/selinux/config 修改SELINUX=disabled 关闭防火墙，停止防火墙自启动 [root@localhost ~]# systemctl stop firewalld [root@localhost ~]# systemctl disable firewalld

8. 内核参数中开启ipv4 forwarding [root@slave1 3]# vim /etc/sysctl.d/99-sysctl.conf 追加net.ipv4.ip_forward = 1

   [root@slave1 3]# vim /etc/sysctl.d/99-sysctl.conf 
   
   # sysctl settings are defined through files in
   # /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.
   #
   # Vendors settings live in /usr/lib/sysctl.d/.
   # To override a whole file, create a new file with the same in
   # /etc/sysctl.d/ and put new settings there. To override
   # only specific settings, add a file with a lexically later
   # name in /etc/sysctl.d/ and put new settings there.
   #
   # For more information, see sysctl.conf(5) and sysctl.d(5).
   net.ipv4.ip_forward = 1
   

9. 增加nat规则，并删除forward中的拒绝规则 增加nat规则：将源地址为vpn网段10.8.0.0/24地址的源地址掩饰为内网地址10.1.30.100 [root@localhost ~]# iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -j SNAT --to-source 10.1.30.100 查看规则 [root@localhost ~]# iptables -nL --line-number 根据序号删除FORWARD中为REJECT的规则 [root@localhost ~]# iptables -D FORWARD 5 [root@localhost ~]# iptables -D FORWARD 4

10. 映射内网1194端口至公网 并在路由器或者核心交换机增加一条10.8.0.0/24出口为10.1.30.100的静态路由

二、客户端配置(Windows)

1. 下载客户端并安装
2. 从服务器端下载以下证书秘钥并放入安装目录的config下， 默认安装目录为C:\Program Files\OpenVPN /etc/openvpn/server/ca.crt /etc/openvpn/server/ta.key /etc/openvpn/server/issued/client1.crt /etc/openvpn/server/private/client1.key

   [root@slave1 server]# cd /etc/openvpn/server
   [root@slave1 server]# ll
   total 32
   -rw-------. 1 root root  1172 Feb  6 01:00 ca.crt
   -rw-------. 1 root root   424 Feb  6 01:25 dh.pem
   -rw-------. 1 root root     0 Feb  6 02:06 ipp.txt
   drwx------. 2 root root    44 Feb  6 01:19 issued
   -rw-------. 1 root root  1128 Feb  6 01:56 openvpn.log
   -rw-------. 1 root root   505 Feb  6 02:07 openvpn-status.log
   drwx------. 2 root root    58 Feb  6 01:19 private
   -rw-r--r--. 1 root root 12182 Feb  6 01:56 server.conf
   -rw-------. 1 root root   636 Feb  6 01:29 ta.key

   如下图所示
3. 在C:\Program Files\OpenVPN\config下创建client1.ovpn并编辑

   ##############################################
   # 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.
   # 申明指定为客户端
   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.
   # 申明使用的设备可选tap基于桥接模式和tun基于路由模式，tap是二层设备，支持链路层协议。
   ;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.
   # 申明使用的协议，默认使用UDP，如果使用HTTP proxy，必须使用TCP协议,如果采用了tcp,需要注释最后的--explicit-exit-notify     can only be used with --proto udp
   ;proto tcp
   proto udp
   
   # The hostname/IP and port of the server.
   # You can have multiple remote entries
   # to load balance between the servers.
   # OpenVPN服务器的外网IP和端口
   remote *.*.*.* 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证书，client1的证书和密钥，默认在安装目录的connfig目录下
   ca ca.crt
   cert client1.crt
   key client1.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.
   # 指定ta.key位置，此处服务器为0，客户端为1
   tls-auth ta.key 1
   key-direction  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
   cipher AES-256-CBC
   
   # 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

4. 打开OpenVPN GUI 连接VPN

三、增加用户名密码验证实现秘钥+密码双重验证

1. 修改服务器端server.conf [root@localhost ~]# vim /etc/openvpn/server/server.conf 追加如下配置

   # 用户名密码验证脚本
   auth-user-pass-verify /etc/openvpn/checkpsw.sh via-env
   # 让客户端输入用户名和密码如果正确才允许访问
   username-as-common-name
   script-security 3

2. 密码验证脚本 [root@localhost ~]# vim /etc/openvpn/checkpsw.sh

   [root@localhost ~]# vim /etc/openvpn/checkpsw.sh
   
   #!/bin/sh
   ###########################################################
   # checkpsw.sh (C) 2004 Mathias Sundman <[email protected]>
   #
   # This script will authenticate OpenVPN users against
   # a plain text file. The passfile should simply contain
   # one row per user with the username first followed by
   # one or more space(s) or tab(s) and then the password.
   PASSFILE="/etc/openvpn/psw-file"
   LOG_FILE="/var/log/openvpn-password.log"
   TIME_STAMP=`date "+%Y-%m-%d %T"`
   ###########################################################
   if [ ! -r "${PASSFILE}" ]; then
     echo "${TIME_STAMP}: Could not open password file \"${PASSFILE}\" for reading." >> ${LOG_FILE}
     exit 1
   fi
   CORRECT_PASSWORD=`awk '!/^;/&&!/^#/&&$1=="'${username}'"{print $2;exit}' ${PASSFILE}`
   if [ "${CORRECT_PASSWORD}" = "" ]; then
     echo "${TIME_STAMP}: User does not exist: username=\"${username}\", password=\"${password}\"." >> ${LOG_FILE}
     exit 1
   fi
   if [ "${password}" = "${CORRECT_PASSWORD}" ]; then
     echo "${TIME_STAMP}: Successful authentication: username=\"${username}\"." >> ${LOG_FILE}
     exit 0
   fi
   echo "${TIME_STAMP}: Incorrect password: username=\"${username}\", password=\"${password}\"." >> ${LOG_FILE}
   exit 1

3. 创建用户和密码认证文件 [root@localhost ~]# vim /etc/openvpn/psw-file

   [root@localhost ~]# vim /etc/openvpn/psw-file
   # 每行一条，用户名密码用空格隔开
   admin password

4. 重启openvpn服务端 [root@slave1 server]# systemctl restart openvpn-server@server

5. 客户端.ovpn文件配置增加密码验证框显示 配置文件追加如下

   # 用户名密码显示框
   auth-user-pass

6. 用户名密码验证连接