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第 42 章 VPN (Virtual Private Network)

目錄

42.1. OpenVPN (openvpn - Virtual Private Network daemon)
42.1.1. 源碼安裝
42.1.2. Openvpn Server
42.1.2.1. create keys for the server
42.1.2.2. create keys for the clients
42.1.3. openvpn - secure IP tunnel daemon.
42.1.4. 吊銷(revoke)用戶證書
42.1.5. Openvpn Client
42.1.6. OpenVPN GUI for Windows
42.1.6.1. Windows Server
42.1.6.2. Windows Client
42.1.7. point-to-point VPNs
42.1.8. VPN 案例
42.1.8.1. server and client vpn
42.1.8.2. Ethernet Bridging Example
42.1.8.3. IDC Example
42.1.9. OpenVPN安全
42.2. pptpd
42.2.1. Server 服務端
42.2.2. Client 客戶端
42.2.2.1. 創建賬號
42.2.2.2. 內核模組安裝
42.2.2.3. 撥入VPN
42.2.2.4. 路由配置
42.2.3. FAQ
42.2.3.1. 800 錯誤
42.2.3.2. 測試 PPTP 連接埠
42.2.3.3. debug
42.3. l2tpd - dummy package for l2tpd to xl2tpd transition
42.4. strongswan - IPSec utilities for strongSwan
42.4.1. 安裝 strongswan VPN 伺服器
42.4.2. 防火牆配置
42.4.3. 配置 IPSEC
42.4.4. Windows 10 VPN 客戶端配置
42.4.5. FAQ
42.4.5.1. 查看證書信息
42.5. openswan - IPSEC utilities for Openswan
42.6. Ipsec VPN
42.6.1. ipsec-tools - IPsec tools for Linux
42.7. N2N VPN
42.8. Hypersocket VPN

42.1. OpenVPN (openvpn - Virtual Private Network daemon)

http://openvpn.net/

42.1.1. 源碼安裝

過程 42.1. OpenVPN 編譯安裝步驟

  1. 安裝liblzo,libssl支持庫

    netkiller@neo:~$ sudo apt-get install liblzo-dev
    netkiller@neo:~$ sudo apt-get install libssl-dev
    				
  2. 取得安裝包

    netkiller@neo:/usr/local$ sudo chmod 777 /usr/local/src/
    netkiller@neo:~$ cd /usr/local/src/
    netkiller@neo:/usr/local/src$ wget http://openvpn.net/release/openvpn-2.0.9.tar.gz
    netkiller@neo:/usr/local/src$ tar zxvf openvpn-2.0.9.tar.gz
    netkiller@neo:/usr/local/src$ cd openvpn-2.0.9/
    netkiller@neo:/usr/local/src/openvpn-2.0.9$
    				
  3. 編譯安裝

    netkiller@neo:/usr/local/src/openvpn-2.0.9$ ./configure --prefix=/usr/local/openvpn-2.0.9 --enable-pthread
    netkiller@neo:/usr/local/src/openvpn-2.0.9$ make
    netkiller@neo:/usr/local/src/openvpn-2.0.9$ sudo make install
    				
  4. 配置檔案

    netkiller@neo:/usr/local/src/openvpn-2.0.9$ sudo ln -s /usr/local/openvpn-2.0.9/ /usr/local/openvpn
    netkiller@neo:/usr/local/src/openvpn-2.0.9$ cd /usr/local/openvpn
    netkiller@neo:/usr/local/openvpn$ sudo mkdir etc
    netkiller@neo:/usr/local/openvpn$ sudo mkdir log
    netkiller@neo:/usr/local/openvpn$ sudo vi etc/openvpn.conf
    				

    例 42.1. openvpn.conf

    
    					

    sudo cp ca.crt dh1024.pem server.crt server.key /usr/local/openvpn/etc/


  5. 創建證書

    修改vars檔案的環境變數

    netkiller@neo:/usr/share/openvpn$ sudo vi vars
    export KEY_COUNTRY=CN
    export KEY_PROVINCE=GD
    export KEY_CITY=Shenzhen
    export KEY_ORG=http://netkiller.sourceforge.net/
    export KEY_EMAIL=openunix@163.com
    				
    netkiller@neo:/usr/local/openvpn$ cd /usr/share/openvpn/
    netkiller@neo:/usr/share/openvpn$
    
    netkiller@neo:~/openvpn-2.1_rc1/easy-rsa/2.0$ sudo make install DESTDIR=/usr/share/openvpn
    install -c --directory "/usr/share/openvpn/"
    install -c --mode=0755 build-* "/usr/share/openvpn/"
    install -c --mode=0755 clean-all list-crl inherit-inter pkitool revoke-full sign-req whichopensslcnf "/usr/share/openvpn/"
    install -c --mode=0644 openssl-0.9.6.cnf openssl.cnf README vars "/usr/share/openvpn/"
    netkiller@neo:~/openvpn-2.1_rc1/easy-rsa/2.0$
    
    netkiller@neo:/usr/share/openvpn$ sudo chmod +x vars
    netkiller@neo:/usr/share/openvpn$
    netkiller@neo:/usr/share/openvpn$ sudo ./clean-all
    
    netkiller@neo:/usr/share/openvpn$ sudo ./build-ca
    netkiller@neo:/usr/share/openvpn$ sudo ./build-key-server server
    netkiller@neo:/usr/share/openvpn$ sudo ./build-key client1
    
    netkiller@neo:/usr/share/openvpn$ sudo mkdir /etc/openvpn
    netkiller@neo:/usr/share/openvpn$ cd /etc/openvpn/
    netkiller@neo:/etc/openvpn$ sudo vi server.ovpn
    netkiller@neo:/etc/openvpn$ sudo cp /usr/share/openvpn/keys/dh1024.pem .
    netkiller@neo:/etc/openvpn$ sudo cp /usr/share/openvpn/keys/server.crt .
    netkiller@neo:/etc/openvpn$ sudo cp /usr/share/openvpn/keys/server.key .
    netkiller@neo:/etc/openvpn$ sudo cp /usr/share/openvpn/keys/ca.crt .
    
    root@neo:/home/netkiller/openvpn-2.1_rc1/sample-config-files# cp * /etc/openvpn/
    root@neo:/home/netkiller/openvpn-2.1_rc1/sample-config-files# cd /etc/openvpn/
    				
  6. 啟動

    /usr/local/openvpn/sbin/openvpn --config /usr/local/openvpn/etc/openvpn.conf
    				
  7. Script

    /etc/init.d/openvpn

    				
    #!/bin/bash
    # vpn init file for OpenVPN
    #
    # chkconfig: - 100 100
    # description: OpenVPN is a full-featured SSL VPN solution which can accomodate a wide range of configurations,
    #				including remote access, site-to-site VPNs, WiFi security,
    #				and enterprise-scale remote access solutions with load balancing, failover,
    #				and fine-grained access-controls
    #				as it is designed and optimized for high performance environments.
    # author: Neo Chen<openunix@163.com>
    #
    # processname: $PROG
    # config:
    # pidfile: /var/run/openvpn
    
    # source function library
    . /etc/init.d/functions
    
    PREFIX=/usr/local/openvpn
    PROG=$PREFIX/sbin/openvpn
    OPTIONS="-f /usr/local/openvpn/etc/openvpn.conf"
    USER=daemon
    RETVAL=0
    prog="openvpn"
    
    start() {
            echo -n $"Starting $prog: "
            if [ $UID -ne 0 ]; then
                    RETVAL=1
                    failure
            else
                    daemon --user=$USER $PROG $OPTIONS
                    RETVAL=$?
                    [ $RETVAL -eq 0 ] && touch /var/lock/subsys/openvpn
            fi;
            echo
            return $RETVAL
    }
    
    stop() {
            echo -n $"Stopping $prog: "
            if [ $UID -ne 0 ]; then
                    RETVAL=1
                    failure
            else
                    killproc $PROG
                    RETVAL=$?
                    [ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/openvpn
            fi;
            echo
            return $RETVAL
    }
    
    reload(){
            echo -n $"Reloading $prog: "
            killproc $PROG -HUP
            RETVAL=$?
            echo
            return $RETVAL
    }
    
    restart(){
    	stop
    	start
    }
    
    condrestart(){
        [ -e /var/lock/subsys/openvpn ] && restart
        return 0
    }
    
    case "$1" in
      start)
    	start
    	;;
      stop)
    	stop
    	;;
      restart)
    	restart
            ;;
      reload)
    	reload
            ;;
      condrestart)
    	condrestart
    	;;
      status)
            status openvpn
    	RETVAL=$?
            ;;
      *)
    	echo $"Usage: $0 {start|stop|status|restart|condrestart|reload}"
    	RETVAL=1
    esac
    
    exit $RETVAL
    				
    				

    添加x權限

    sudo chmod +x /etc/init.d/openvpn
    				

42.1.2. Openvpn Server

Ubuntu/Debian 環境安裝

過程 42.2. Openvpn Server 安裝步驟

  • 相關軟件包

    netkiller@shenzhen:~$ apt-cache search openvpn
    carpaltunnel - Configuration helper for OpenVPN
    kvpnc - vpn clients frontend for KDE
    network-manager-openvpn - network management framework (OpenVPN plugin)
    openvpn - Virtual Private Network daemon
    tunneldigger - Configures OpenVPN tunnel networks
    tunneldigger-utils - Utilities for TunnelDigger-configured OpenVPN tunnels
    You have new mail in /var/mail/netkiller
    netkiller@shenzhen:~$
    				

    This is for Dapper ubuntu and openvpn

    netkiller@shenzhen:~$ sudo apt-get install openvpn
    				
    • config file

      /etc/openvpn/

    • share

      /usr/share/openvpn/

    • doc

      /usr/share/doc/openvpn/

    • example

      /usr/share/doc/openvpn/examples/

42.1.2.1. create keys for the server

過程 42.3. CREATE KEYS FOR THE SERVER AND THE CLIENTS

  1. Change to the directory /usr/share/doc/openvpn/examples/easy-rsa/2.0

    netkiller@shenzhen:~$ cd /usr/share/doc/openvpn/examples/easy-rsa/2.0
    netkiller@shenzhen:/usr/share/doc/openvpn/examples/easy-rsa/2.0$ ls
    build-ca  build-dh  build-inter  build-key  build-key-pass  build-key-pkcs12  build-key-server  build-req  build-req-pass  clean-all  inherit-inter  list-crl  Makefile  openssl-0.9.6.cnf.gz  openssl.cnf  pkitool  README.gz  revoke-full  sign-req  vars  whichopensslcnf
    					

    backup vars to vars.original

    sudo cp vars vars.original
    					

    vi vars and change with you

    export KEY_COUNTRY="CN"
    export KEY_PROVINCE="GD"
    export KEY_CITY="Shenzhen"
    export KEY_ORG="http://netkiller.sourceforge.net/"
    export KEY_EMAIL="openunix@163.com"
    					

    type the commands

    • vars

    • clean-all

    • build-ca

    • build-key-server server

    • build-key client1

    • build-dh

  2. vars and clean-all

    netkiller@shenzhen:/usr/share/doc/openvpn/examples/easy-rsa/2.0$ source ./vars
    NOTE: If you run ./clean-all, I will be doing a rm -rf on /usr/share/doc/openvpn/examples/easy-rsa/2.0/keys
    netkiller@shenzhen:/usr/share/doc/openvpn/examples/easy-rsa/2.0$ ./clean-all
    
    $ sudo mkdir keys
    $ sudo chown neo.neo keys
    					
  3. build-ca

    netkiller@shenzhen:/usr/share/doc/openvpn/examples/easy-rsa/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) [GD]:
    Locality Name (eg, city) [Shenzhen]:
    Organization Name (eg, company) [http://netkiller.8800.org]:
    Organizational Unit Name (eg, section) []:
    Common Name (eg, your name or your server's hostname) [http://netkiller.8800.org CA]:
    Email Address [openunix@163.com]:
    					
  4. build-key-server server

    You will have to answer the same questions above. It will ask you for a password, I suggest you don’t put a password when it ask.

    netkiller@shenzhen:/usr/share/doc/openvpn/examples/easy-rsa/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) [GD]:
    Locality Name (eg, city) [Shenzhen]:
    Organization Name (eg, company) [http://netkiller.8800.org]:
    Organizational Unit Name (eg, section) []:
    Common Name (eg, your name or your server's hostname) [server]:
    Email Address [openunix@163.com]:
    
    Please enter the following 'extra' attributes
    to be sent with your certificate request
    A challenge password []:
    An optional company name []:
    Using configuration from /usr/share/doc/openvpn/examples/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:'GD'
    localityName          :PRINTABLE:'Shenzhen'
    organizationName      :PRINTABLE:'http://netkiller.8800.org'
    commonName            :PRINTABLE:'server'
    emailAddress          :IA5STRING:'openunix@163.com'
    Certificate is to be certified until Nov 10 18:09:52 2017 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
    					

    enter yes to sign the certificate.

  5. build-dh

    # ./build-dh
    Generating DH parameters, 1024 bit long safe prime, generator 2
    This is going to take a long time
    .........................+..............................+....................................................+..........................................................................................+............................................................+..........................................+..........................+.............................................................................................................+....................+...................+...............................................+..+...........................................................+................+..........................................................+............................................................................+..........+..........................................................................+...........+.............................................................................................................................................................................+....+..........................................................+........+...................................+.........................................................+...........................................................................................+..............................................................................................+.................................++*++*++*
    					

42.1.2.2. create keys for the clients

過程 42.4. create keys for the clients

  1. build-key client1

    Now to build the client files

    netkiller@shenzhen:/usr/share/doc/openvpn/examples/easy-rsa/2.0$ ./build-key client1
    Generating a 1024 bit RSA private key
    .++++++
    ...........++++++
    writing new private key to 'client1.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) [GD]:
    Locality Name (eg, city) [Shenzhen]:
    Organization Name (eg, company) [http://netkiller.8800.org]:
    Organizational Unit Name (eg, section) []:
    Common Name (eg, your name or your server's hostname) [client1]:
    Email Address [openunix@163.com]:
    
    Please enter the following 'extra' attributes
    to be sent with your certificate request
    A challenge password []:
    An optional company name []:
    Using configuration from /usr/share/doc/openvpn/examples/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:'GD'
    localityName          :PRINTABLE:'Shenzhen'
    organizationName      :PRINTABLE:'http://netkiller.8800.org'
    commonName            :PRINTABLE:'client1'
    emailAddress          :IA5STRING:'openunix@163.com'
    Certificate is to be certified until Nov 10 18:15:39 2017 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
    				

    And once again you will need to answer the questions above. I still don’t recommend you putting a password as it can cause problems when I have tried.

    注意在進入 Common Name (eg, your name or your server's hostname) []: 的輸入時, 每個證書輸入的名字必須不同.

  2. All the files you just generated are located in /usr/share/doc/openvpn/examples/easy-rsa/2.0/keys

    If you do a list command in the keys folder you should have something like:

    netkiller@shenzhen:/usr/share/doc/openvpn/examples/easy-rsa/2.0$ ls keys/
    01.pem  ca.crt  client1.crt  client1.key  index.txt       index.txt.attr.old  serial      server.crt  server.key
    02.pem  ca.key  client1.csr  dh1024.pem   index.txt.attr  index.txt.old       serial.old  server.csr
    			

    Copy the files ca.crt, ca.key, dh1024.pem, server.crt, and server.key to the /etc/openvpn/keys

    netkiller@shenzhen:/usr/share/doc/openvpn/examples/easy-rsa/2.0$ cd keys/
    netkiller@shenzhen:/usr/share/doc/openvpn/examples/easy-rsa/2.0/keys$ sudo cp keys/ca.key keys/ca.crt keys/dh1024.pem keys/server.key keys/server.crt /etc/openvpn/
    				

    We will worry about the client files after we configure the client config file.

  3. CONFIGURE THE SERVER

    Change to the directory /usr/share/doc/openvpn/examples/sample-config-files

    netkiller@shenzhen:/usr/share/doc/openvpn/examples/sample-config-files$ sudo gunzip server.conf.gz
    netkiller@shenzhen:/usr/share/doc/openvpn/examples/sample-config-files$ sudo cp server.conf /etc/openvpn/
    netkiller@shenzhen:/usr/share/doc/openvpn/examples/sample-config-files$ cd /etc/openvpn/
    netkiller@shenzhen:/etc/openvpn$
    			

    為用戶添加路由

    push "route 192.168.1.0 255.255.255.0"

    例 42.2. 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 a.b.c.d
    ;local 192.168.1.7
    
    # 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
    
    # "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 ca.crt
    cert server.crt
    key 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 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 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
    
    # 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"
    push "route 192.168.1.0 255.255.255.0"
    
    # 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
    # the TUN/TAP interface to the internet in
    # order for this to work properly).
    # CAVEAT: May break client's network config if
    # client's local DHCP server packets get routed
    # through the tunnel.  Solution: make sure
    # client's local DHCP server is reachable via
    # a more specific route than the default route
    # of 0.0.0.0/0.0.0.0.
    ;push "redirect-gateway"
    
    # Certain Windows-specific network settings
    # can be pushed to clients, such as DNS
    # or WINS server addresses.  CAVEAT:
    # http://openvpn.net/faq.html#dhcpcaveats
    ;push "dhcp-option DNS 10.8.0.1"
    ;push "dhcp-option WINS 10.8.0.1"
    
    # 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
    
    # 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 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 nogroup
    
    # 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 3
    
    # Silence repeating messages.  At most 20
    # sequential messages of the same message
    # category will be output to the log.
    ;mute 20
    					
    					

    test

    netkiller@shenzhen:/etc/openvpn$ sudo openvpn --config /etc/openvpn/server.conf
    Tue Nov 13 14:12:33 2007 OpenVPN 2.0.9 i486-pc-linux-gnu [SSL] [LZO] [EPOLL] built on Mar  2 2007
    Tue Nov 13 14:12:33 2007 Diffie-Hellman initialized with 1024 bit key
    Tue Nov 13 14:12:33 2007 TLS-Auth MTU parms [ L:1542 D:138 EF:38 EB:0 ET:0 EL:0 ]
    Tue Nov 13 14:12:33 2007 TUN/TAP device tun0 opened
    Tue Nov 13 14:12:33 2007 ifconfig tun0 10.8.0.1 pointopoint 10.8.0.2 mtu 1500
    Tue Nov 13 14:12:33 2007 route add -net 10.8.0.0 netmask 255.255.255.0 gw 10.8.0.2
    Tue Nov 13 14:12:33 2007 Data Channel MTU parms [ L:1542 D:1450 EF:42 EB:135 ET:0 EL:0 AF:3/1 ]
    Tue Nov 13 14:12:33 2007 UDPv4 link local (bound): [undef]:1194
    Tue Nov 13 14:12:33 2007 UDPv4 link remote: [undef]
    Tue Nov 13 14:12:33 2007 MULTI: multi_init called, r=256 v=256
    Tue Nov 13 14:12:33 2007 IFCONFIG POOL: base=10.8.0.4 size=62
    Tue Nov 13 14:12:33 2007 IFCONFIG POOL LIST
    Tue Nov 13 14:12:33 2007 Initialization Sequence Completed
    				
  4. firewall 配置

    iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
    iptables -A FORWARD -i eth0 -o tun+ -j ACCEPT
    				

    例 42.3. Openvpn 橋接模式伺服器配置實例

    # Generated by iptables-save v1.4.7 on Sat Jun 15 15:54:31 2013
    *nat
    :PREROUTING ACCEPT [40:5588]
    :POSTROUTING ACCEPT [0:0]
    :OUTPUT ACCEPT [0:0]
    -A POSTROUTING -o br0 -j MASQUERADE
    COMMIT
    # Completed on Sat Jun 15 15:54:31 2013
    # Generated by iptables-save v1.4.7 on Sat Jun 15 15:54:31 2013
    *filter
    :INPUT DROP [0:0]
    :FORWARD DROP [0:0]
    :OUTPUT DROP [81:14706]
    -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
    -A INPUT -p icmp -j ACCEPT
    -A INPUT -i lo -j ACCEPT
    -A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
    -A INPUT -p tcp -m state --state NEW -m tcp --dport 27017 -j ACCEPT
    -A INPUT -p udp --dport 1194 -j ACCEPT
    -A INPUT -j REJECT --reject-with icmp-host-prohibited
    -A FORWARD -i br0 -o tun+ -j ACCEPT
    -A FORWARD -i tun+ -o br0 -j ACCEPT
    -A OUTPUT -j ACCEPT
    COMMIT
    # Completed on Sat Jun 15 15:54:31 2013
    					

    例 42.4. 雙網卡配置實例

    iptables -P INPUT DROP
    iptables -P OUTPUT DROP
    iptables -P FORWARD DROP
    
    iptables -A INPUT -i eth0 -p udp --dport openvpn -j ACCEPT
    iptables -A OUTPUT -o eth0 -p udp --sport openvpn -j ACCEPT
    
    iptables -A INPUT -i tun+ -j ACCEPT
    iptables -A OUTPUT -o tun+ -j ACCEPT
    
    iptables -A FORWARD -i tun+ -o eth1 -j ACCEPT
    iptables -A FORWARD -i eth1 -o tun+ -j ACCEPT
    
    iptables -t nat -A POSTROUTING -s 172.31.0.0/24 -o eth1 -j MASQUERADE
    					

  5. Start

    netkiller@shenzhen:~$ sudo /etc/init.d/openvpn start
    Starting virtual private network daemon: server(OK).
    				

42.1.3. openvpn - secure IP tunnel daemon.

安裝環境CentOS 6.x

過程 42.5. OpenVPN Server

  1. # yum install openvpn easy-rsa
    				

    察看openvpn包中的檔案

    # rpm -ql openvpn
    /etc/openvpn
    /etc/rc.d/init.d/openvpn
    /usr/lib64/openvpn
    /usr/lib64/openvpn/plugin
    /usr/lib64/openvpn/plugin/lib
    /usr/lib64/openvpn/plugin/lib/openvpn-auth-pam.so
    /usr/lib64/openvpn/plugin/lib/openvpn-down-root.so
    /usr/lib64/openvpn/plugins
    /usr/lib64/openvpn/plugins/openvpn-plugin-auth-pam.so
    /usr/lib64/openvpn/plugins/openvpn-plugin-down-root.so
    /usr/sbin/openvpn
    /usr/share/doc/openvpn-2.3.2
    /usr/share/doc/openvpn-2.3.2/AUTHORS
    /usr/share/doc/openvpn-2.3.2/COPYING
    /usr/share/doc/openvpn-2.3.2/COPYRIGHT.GPL
    /usr/share/doc/openvpn-2.3.2/INSTALL
    /usr/share/doc/openvpn-2.3.2/PORTS
    /usr/share/doc/openvpn-2.3.2/README
    /usr/share/doc/openvpn-2.3.2/README.auth-pam
    /usr/share/doc/openvpn-2.3.2/README.down-root
    /usr/share/doc/openvpn-2.3.2/contrib
    /usr/share/doc/openvpn-2.3.2/contrib/OCSP_check
    /usr/share/doc/openvpn-2.3.2/contrib/OCSP_check/OCSP_check.sh
    /usr/share/doc/openvpn-2.3.2/contrib/README
    /usr/share/doc/openvpn-2.3.2/contrib/multilevel-init.patch
    /usr/share/doc/openvpn-2.3.2/contrib/openvpn-fwmarkroute-1.00
    /usr/share/doc/openvpn-2.3.2/contrib/openvpn-fwmarkroute-1.00/README
    /usr/share/doc/openvpn-2.3.2/contrib/openvpn-fwmarkroute-1.00/fwmarkroute.down
    /usr/share/doc/openvpn-2.3.2/contrib/openvpn-fwmarkroute-1.00/fwmarkroute.up
    /usr/share/doc/openvpn-2.3.2/contrib/pull-resolv-conf
    /usr/share/doc/openvpn-2.3.2/contrib/pull-resolv-conf/client.down
    /usr/share/doc/openvpn-2.3.2/contrib/pull-resolv-conf/client.up
    /usr/share/doc/openvpn-2.3.2/sample
    /usr/share/doc/openvpn-2.3.2/sample/Makefile
    /usr/share/doc/openvpn-2.3.2/sample/Makefile.am
    /usr/share/doc/openvpn-2.3.2/sample/Makefile.in
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/README
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/client.conf
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/firewall.sh
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/home.up
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/loopback-client
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/loopback-server
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/office.up
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/openvpn-shutdown.sh
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/openvpn-startup.sh
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/roadwarrior-client.conf
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/roadwarrior-server.conf
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/server.conf
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/static-home.conf
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/static-office.conf
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/tls-home.conf
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/tls-office.conf
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/xinetd-client-config
    /usr/share/doc/openvpn-2.3.2/sample/sample-config-files/xinetd-server-config
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys/README
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys/ca.crt
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys/ca.key
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys/client.crt
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys/client.key
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys/dh1024.pem
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys/pass.crt
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys/pass.key
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys/pkcs12.p12
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys/server.crt
    /usr/share/doc/openvpn-2.3.2/sample/sample-keys/server.key
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/defer
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/defer/README
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/defer/build
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/defer/simple.c
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/defer/simple.def
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/defer/winbuild
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/log
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/log/build
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/log/log.c
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/log/log_v3.c
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/log/winbuild
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/simple
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/simple/README
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/simple/build
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/simple/simple.c
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/simple/simple.def
    /usr/share/doc/openvpn-2.3.2/sample/sample-plugins/simple/winbuild
    /usr/share/doc/openvpn-2.3.2/sample/sample-scripts
    /usr/share/doc/openvpn-2.3.2/sample/sample-scripts/auth-pam.pl
    /usr/share/doc/openvpn-2.3.2/sample/sample-scripts/bridge-start
    /usr/share/doc/openvpn-2.3.2/sample/sample-scripts/bridge-stop
    /usr/share/doc/openvpn-2.3.2/sample/sample-scripts/ucn.pl
    /usr/share/doc/openvpn-2.3.2/sample/sample-scripts/verify-cn
    /usr/share/doc/openvpn-2.3.2/sample/sample-windows
    /usr/share/doc/openvpn-2.3.2/sample/sample-windows/sample.ovpn
    /usr/share/man/man8/openvpn.8.gz
    /usr/share/openvpn
    /var/run/openvpn
    
    # rpm -ql easy-rsa
    /usr/share/doc/easy-rsa-2.2.0
    /usr/share/doc/easy-rsa-2.2.0/COPYING
    /usr/share/doc/easy-rsa-2.2.0/COPYRIGHT.GPL
    /usr/share/doc/easy-rsa-2.2.0/doc
    /usr/share/doc/easy-rsa-2.2.0/doc/Makefile.am
    /usr/share/doc/easy-rsa-2.2.0/doc/README-1.0
    /usr/share/doc/easy-rsa-2.2.0/doc/README-2.0
    /usr/share/easy-rsa
    /usr/share/easy-rsa/2.0
    /usr/share/easy-rsa/2.0/build-ca
    /usr/share/easy-rsa/2.0/build-dh
    /usr/share/easy-rsa/2.0/build-inter
    /usr/share/easy-rsa/2.0/build-key
    /usr/share/easy-rsa/2.0/build-key-pass
    /usr/share/easy-rsa/2.0/build-key-pkcs12
    /usr/share/easy-rsa/2.0/build-key-server
    /usr/share/easy-rsa/2.0/build-req
    /usr/share/easy-rsa/2.0/build-req-pass
    /usr/share/easy-rsa/2.0/clean-all
    /usr/share/easy-rsa/2.0/inherit-inter
    /usr/share/easy-rsa/2.0/list-crl
    /usr/share/easy-rsa/2.0/openssl-0.9.6.cnf
    /usr/share/easy-rsa/2.0/openssl-0.9.8.cnf
    /usr/share/easy-rsa/2.0/openssl-1.0.0.cnf
    /usr/share/easy-rsa/2.0/pkitool
    /usr/share/easy-rsa/2.0/revoke-full
    /usr/share/easy-rsa/2.0/sign-req
    /usr/share/easy-rsa/2.0/vars
    /usr/share/easy-rsa/2.0/whichopensslcnf
    				
  2. key
    # cd /usr/share/openvpn/easy-rsa/2.0/
    
    vim vars
    export KEY_COUNTRY="CN"
    export KEY_PROVINCE="GD"
    export KEY_CITY="Shenzhen"
    export KEY_ORG="http://www.example.com"
    export KEY_EMAIL="neo.chen@example.com"
    
    # chmod +x *
    # cp openssl-1.0.0.cnf openssl.cnf
    
    # source ./vars
    ./clean-all
    ./build-ca
    ./build-key-server server
    ./build-dh
    ./build-key neo
    
    # cp keys/ca.key keys/ca.crt keys/dh1024.pem keys/server.key keys/server.crt /etc/openvpn/
    				
  3. server.conf

    cp keys/ca.key keys/ca.crt keys/dh1024.pem keys/server.key keys/server.crt /etc/openvpn/
    vim /etc/openvpn/server.conf
    				
  4. 啟用IP轉發

    # vim /etc/sysctl.conf
    # Controls IP packet forwarding
    net.ipv4.ip_forward = 1
    				

    net.ipv4.ip_forward = 1 使IP轉發生效

    sysctl -w net.ipv4.ip_forward=1
    				
  5. # /etc/init.d/openvpn start
    Starting openvpn:                                          [  OK  ]
    				

42.1.4. 吊銷(revoke)用戶證書

$ . vars
$ ./revoke-full client1
$ sudo cp keys/crl.pem /etc/openvpn/
		

命令執行完成之後, 會在 keys 目錄下面, 生成一個 crl.pem 檔案,這個檔案中包含了吊銷證書的名單。

確認成功註銷某個證書,可以打開keys/index.txt 檔案,可以看到前面已被標記為R的註銷證書

$ grep ^R keys/index.txt
R       200908052722Z   110218014133Z   04      unknown /C=CN/ST=GD/L=Shenzhen/O=EXAMPLE.COM/CN=client1/emailAddress=client1@EXAMPLE.com
		

在服務端的配置檔案 server.conf 中,加入這樣一行:

crl-verify crl.pem
		

42.1.5. Openvpn Client

$ cd /usr/share/doc/openvpn/examples/easy-rsa/2.0
$ cp keys/ca.crt keys/client1.crt keys/client1.key /etc/openvpn/
		

過程 42.6. Openvpn Client 安裝步驟

  1. CONFIGURE THE CLIENTS

    修改 remote my-server-1 1194

    例 42.5. client.conf

    
    ##############################################
    # 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
    
    # The hostname/IP and port of the server.
    # You can have multiple remote entries
    # to load balance between the servers.
    remote vpn.netkiller.8800.org 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 nogroup
    
    # 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 ca.crt
    cert client1.crt
    key client1.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 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
    
    					

  2. 禁止Server端 redirect-gateway def1

    redirect-gateway local
    				

42.1.6. OpenVPN GUI for Windows

42.1.6.1. Windows Server

過程 42.7. For Windows Server

  1. http://openvpn.se/

    http://openvpn.se/files/install_packages/openvpn-2.0.9-gui-1.0.3-install.exe

    下載安裝後,會在系統托盤上顯示表徵圖.這時並不能使用,使用創建配置檔案後托盤表徵圖才會顯示連接菜單

  2. 創建證書

    C:\Documents and Settings\Neo>cd "\Program Files\OpenVPN\easy-rsa"
    C:\Program Files\OpenVPN\easy-rsa>
    C:\Program Files\OpenVPN\easy-rsa>init-config.bat
    				

    編輯vars.bat

    set KEY_COUNTRY=CN
    set KEY_PROVINCE=GD
    set KEY_CITY=Shenzhen
    set KEY_ORG=netkiller.org.cn
    set KEY_EMAIL=openunix@163.com
    				
    C:\Program Files\OpenVPN\easy-rsa>clean-all.bat
    C:\Program Files\OpenVPN\easy-rsa>vars.bat
    				

    創建CA證書

    				
    C:\Program Files\OpenVPN\easy-rsa>build-ca.bat
    Loading 'screen' into random state - done
    Generating a 1024 bit RSA private key
    ......++++++
    ......++++++
    writing new private key to 'keys\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) [GD]:
    Locality Name (eg, city) [Shenzhen]:
    Organization Name (eg, company) [netkiller.org.cn]:
    Organizational Unit Name (eg, section) []:vpn
    Common Name (eg, your name or your server's hostname) []:netkiller.org.cn
    Email Address [openunix@163.com]:
    
    C:\Program Files\OpenVPN\easy-rsa>
    				
    				

    dh

    				
    C:\Program Files\OpenVPN\easy-rsa>build-dh.bat
    Loading 'screen' into random state - done
    Generating DH parameters, 1024 bit long safe prime, generator 2
    This is going to take a long time
    ..........................+...................+.................................
    .................................+...........+.....................+.......+....
    ...............................................................+..+.............
    .+.......................................+......................................
    ...+..+...........+................................+............................
    ................................................+.....+.........................
    ................................................+.....+......+..................
    ....................................+...........................................
    .........................................................................+.....+
    .......................................+.....................+..................
    ....+...........................................................................
    ......................+............................+............................
    ................................................................................
    ................................................................................
    ............................+.................+......................+......+...
    .............+...................+..............................................
    .................+............................................+.................
    ................................................................................
    ................................+....+.................+........................
    ...................+.......+....................................................
    ..+...............+.............................................................
    ................................................................................
    ...............................................................+................
    .......+.........................................................++*++*++*
    
    C:\Program Files\OpenVPN\easy-rsa>
    				
    				

    server key

    				
    C:\Program Files\OpenVPN\easy-rsa>build-key-server.bat server
    Loading 'screen' into random state - done
    Generating a 1024 bit RSA private key
    ........++++++
    ....................++++++
    writing new private key to 'keys\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) [GD]:
    Locality Name (eg, city) [Shenzhen]:
    Organization Name (eg, company) [netkiller.org.cn]:
    Organizational Unit Name (eg, section) []:vpn
    Common Name (eg, your name or your server's hostname) []:netkiller.org.cn
    Email Address [openunix@163.com]:
    
    Please enter the following 'extra' attributes
    to be sent with your certificate request
    A challenge password []:chen
    An optional company name []:
    Using configuration from openssl.cnf
    Loading 'screen' into random state - done
    Check that the request matches the signature
    Signature ok
    The Subject's Distinguished Name is as follows
    countryName           :PRINTABLE:'CN'
    stateOrProvinceName   :PRINTABLE:'GD'
    localityName          :PRINTABLE:'Shenzhen'
    organizationName      :PRINTABLE:'netkiller.org.cn'
    organizationalUnitName:PRINTABLE:'vpn'
    commonName            :PRINTABLE:'netkiller.org.cn'
    emailAddress          :IA5STRING:'openunix@163.com'
    Certificate is to be certified until Jun  9 03:14:55 2017 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
    
    C:\Program Files\OpenVPN\easy-rsa>
    				
    				

    client key

    				
    C:\Program Files\OpenVPN\easy-rsa>build-key.bat client
    Loading 'screen' into random state - done
    Generating a 1024 bit RSA private key
    ......++++++
    ....................++++++
    writing new private key to 'keys\client.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) [GD]:
    Locality Name (eg, city) [Shenzhen]:
    Organization Name (eg, company) [netkiller.org.cn]:
    Organizational Unit Name (eg, section) []:vpn
    Common Name (eg, your name or your server's hostname) []:netkiller.org.cn
    Email Address [openunix@163.com ]:
    
    Please enter the following 'extra' attributes
    to be sent with your certificate request
    A challenge password []:chen
    An optional company name []:
    Using configuration from openssl.cnf
    Loading 'screen' into random state - done
    DEBUG[load_index]: unique_subject = "yes"
    Check that the request matches the signature
    Signature ok
    The Subject's Distinguished Name is as follows
    countryName           :PRINTABLE:'CN'
    stateOrProvinceName   :PRINTABLE:'GD'
    localityName          :PRINTABLE:'Shenzhen'
    organizationName      :PRINTABLE:'netkiller.org.cn'
    organizationalUnitName:PRINTABLE:'vpn'
    commonName            :PRINTABLE:'netkiller.org.cn'
    emailAddress          :IA5STRING:'openunix@163.com^I'
    Certificate is to be certified until Jun  9 03:17:55 2017 GMT (3650 days)
    Sign the certificate? [y/n]:y
    failed to update database
    TXT_DB error number 2
    
    C:\Program Files\OpenVPN\easy-rsa>
    				
    				
  3. 配置

    例 42.6. server.ovpn

    
    #################################################
    # 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
    
    # "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 ca.crt
    cert server.crt
    key 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 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 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
    
    # 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
    # the TUN/TAP interface to the internet in
    # order for this to work properly).
    # CAVEAT: May break client's network config if
    # client's local DHCP server packets get routed
    # through the tunnel.  Solution: make sure
    # client's local DHCP server is reachable via
    # a more specific route than the default route
    # of 0.0.0.0/0.0.0.0.
    ;push "redirect-gateway"
    
    # Certain Windows-specific network settings
    # can be pushed to clients, such as DNS
    # or WINS server addresses.  CAVEAT:
    # http://openvpn.net/faq.html#dhcpcaveats
    ;push "dhcp-option DNS 10.8.0.1"
    ;push "dhcp-option WINS 10.8.0.1"
    
    # 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
    
    # 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 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 3
    
    # Silence repeating messages.  At most 20
    # sequential messages of the same message
    # category will be output to the log.
    ;mute 20
    
    
    					

42.1.6.2. Windows Client

過程 42.8. For Windows Client

  1. 配置檔案

    將C:\Program Files\OpenVPN\sample-config目錄下的client.ovpn複製到C:\Program Files\OpenVPN\config

    ca.crt, client.crt, client.key 三個檔案複製到 C:\Program Files\OpenVPN\config

    修改;remote my-server-1 1194

    remote vpn.netkiller.8800.org 1194
    					

    編輯client.ovpn檔案

    例 42.7. client.ovpn

    ##############################################
    # 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
    
    # The hostname/IP and port of the server.
    # You can have multiple remote entries
    # to load balance between the servers.
    remote netkiller.8800.org 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.
    ca ca.crt
    cert client1.crt
    key client1.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 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
    						

  2. 連接到VPN伺服器

    托盤表徵圖上->右鍵->選擇 [Connect] 菜單

42.1.6.2.1. 客戶端路由設置

client.ovpn 中加入

# Silence repeating messages
;mute 20
up client.ovpn_up.bat
				

client.ovpn_up.bat

				
@echo off
@echo 5秒後執行添加路由
set t=5
ping -n %t% 127.0.0.1>nul
@echo 開始執行添加路由

route ADD 0.0.0.0 MASK 0.0.0.0 192.168.90.254

route DELETE 0.0.0.0 MASK 128.0.0.0 10.8.0.21
route DELETE 128.0.0.0 MASK 128.0.0.0 10.8.0.21


rem route ADD 10.0.0 MASK 255.0.0.0 192.168.90.252
rem route ADD 192.168.0 MASK 255.255.0.0 192.168.90.252
rem route ADD 202.96.0.0 MASK 255.255.0.0 192.168.90.252
				
				

42.1.7. point-to-point VPNs

過程 42.9. This example demonstrates a bare-bones point-to-point OpenVPN configuration.

  1. Generate a static key

    $ cd /etc/openvpn/
    $ sudo openvpn --genkey --secret static.key
    				
  2. server configuration file

    $ cd /usr/share/doc/openvpn/examples/sample-config-files
    $ sudo cp static-office.conf office.up /etc/openvpn/
    				

    static-office.conf

    $ sudo vim static-office.conf
    				
  3. client configuration file

    $ cd /usr/share/doc/openvpn/examples/sample-config-files
    $ sudo cp static-home.conf home.up /etc/openvpn/
    $ cd /etc/openvpn/
    $ scp user@netkiller.8800.org:/etc/openvpn/static.key .
    				

    static-home.conf

    remote netkiller.8800.org
    				

OpenVPN GUI for Windows

copy C:\Program Files\OpenVPN\sample-config\sample.ovpn C:\Program Files\OpenVPN\config
		

42.1.8. VPN 案例

42.1.8.1. server and client vpn

		
office (linux)                                   home (xp)
--------------                                   ----------
172.16.0.1 eth0                                  192.168.0.1
    ^                                                ^
    |                                                |
10.8.0.1 tun0  --> 10.8.0.2 <---> 10.8.0.5 <--   10.8.0.6

testing home - > office
----------------------------------------------------------

ping 10.8.0.1 OK
ping 172.16.0.1 OK
ping 172.16.0.254 OK
		
		

例 42.8. office.conf

office

			
$ sudo sysctl -w net.ipv4.ip_forward=1
$ sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
			
			
			
#################################################
# 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

# "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 ca.crt
cert server.crt
key 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 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 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"
push "route 172.16.0.0 255.255.255.0"

# 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
route 192.168.102.0 255.255.255.0
# 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"

# 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"

# 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

# 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 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 nogroup

# 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 3

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

例 42.9. home.ovpn

			
##############################################
# 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

# The hostname/IP and port of the server.
# You can have multiple remote entries
# to load balance between the servers.
remote netkiller.8800.org 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.
ca ca.crt
cert client.crt
key client.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 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
			
			

42.1.8.2. Ethernet Bridging Example

過程 42.10. server

  1. yum -y install bridge-utils
    				
  2. server.conf

    dev tap0
    server-bridge 192.168.3.5 255.255.255.0 192.168.3.200  192.168.3.250
    push "redirect-gateway local def1"
    push "dhcp-option DNS 208.67.222.222"
    push "dhcp-option DNS 208.67.220.220"
    				
  3. cp /usr/share/doc/openvpn-2.1.1/sample-scripts/bridge-st* /etc/openvpn/
    chmod +x /etc/openvpn/bridge*
    				

    config bridge-start

    vim /etc/openvpn/bridge-start
    eth="eth0"
    eth_ip="192.168.3.5"
    eth_netmask="255.255.255.0"
    eth_broadcast="192.168.3.255"
    				
  4. start

    /etc/openvpn/bridge-start
    /etc/init.d/openvpn start
    				
  5. stop

    /etc/init.d/openvpn stop
    /etc/openvpn/bridge-stop
    				

過程 42.11. client

  1. client.ovpn

    dev tap
    dev-node tap-bridge
    				
  2. 網路上的芳鄰右鍵,選擇屬性,TAP-Win32 Adapter V8 重命名為 tap-bridge

    vista windows7 操作系統注意:

    OpenVPN GUI 右鍵“以管理員身份運行”
    
    client.ovpn 中加入
    route-method exe
    route-delay 2
    				

42.1.8.3. IDC Example

		Internet
			|
			V
		ethernet 0 : 120.132.x.x
	Cisco PIX Firewall	NAT(120.132.x.x TO 172.16.1.2)
		ethernet 1 : 172.16.1.254
			|
			V
Cisco Catalyst 3750 Switch
		g0/0/1 : 172.16.1.1
			|
			V
	eth0 : 172.16.1.2
	OpenVPN Server
		

VPN 撥通後不能正常訪問172.16.1.0

/etc/openvpn/server.conf

push "redirect-gateway def1 bypass-dhcp"
		
$ sudo iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE
		

42.1.9. OpenVPN安全

OpenVPN 一旦撥通,即可訪問LAN內所有資源。很多時候我們並不希望所有的電腦都被訪問。有兩種方法:

通過 push 是用戶無法訪問某些網段

通過iptables限制訪問規則

# Generated by iptables-save v1.4.7 on Tue May 14 17:54:27 2013
*nat
:PREROUTING ACCEPT [223:25375]
:POSTROUTING ACCEPT [14:949]
:OUTPUT ACCEPT [14:949]
-A POSTROUTING -s 10.8.0.0/24 -o br0 -j MASQUERADE
COMMIT
# Completed on Tue May 14 17:54:27 2013
# Generated by iptables-save v1.4.7 on Tue May 14 17:54:27 2013
*mangle
:PREROUTING ACCEPT [11437:6020321]
:INPUT ACCEPT [3297:437320]
:FORWARD ACCEPT [8084:5579781]
:OUTPUT ACCEPT [5861:5797640]
:POSTROUTING ACCEPT [13949:11377549]
-A POSTROUTING -o virbr0 -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill
COMMIT
# Completed on Tue May 14 17:54:27 2013
# Generated by iptables-save v1.4.7 on Tue May 14 17:54:27 2013
*filter
:INPUT ACCEPT [300:38586]
:FORWARD ACCEPT [736:520323]
:OUTPUT ACCEPT [503:536634]
-A FORWARD -d 192.168.2.10/32 -i tun0 -p tcp --dport 80 -j ACCEPT
-A FORWARD -d 192.168.2.11/32 -i tun0 -p tcp --dport 80 -j ACCEPT
-A FORWARD -d 192.168.2.12/32 -i tun0 -p tcp --dport 80 -j ACCEPT
-A FORWARD -d 192.168.2.13/32 -i tun0 -p tcp --dport 80 -j ACCEPT
-A FORWARD -d 192.168.2.14/32 -i tun0 -p tcp --dport 80 -j ACCEPT
-A FORWARD -d 192.168.0.0/16 -i tun0 -j DROP
COMMIT
# Completed on Tue May 14 17:54:27 2013
		

查詢生效規則

# iptables -L -v
Chain INPUT (policy ACCEPT 226 packets, 17012 bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination
    0     0 ACCEPT     tcp  --  tun0   any     anywhere             192.168.2.10        tcp dpt:http
    0     0 ACCEPT     tcp  --  tun0   any     anywhere             192.168.2.11        tcp dpt:http
    0     0 ACCEPT     tcp  --  tun0   any     anywhere             192.168.2.12        tcp dpt:http
    0     0 ACCEPT     tcp  --  tun0   any     anywhere             192.168.2.13        tcp dpt:http
    0     0 ACCEPT     tcp  --  tun0   any     anywhere             192.168.2.14        tcp dpt:http
    0     0 DROP       all  --  tun0   any     anywhere             192.168.0.0/16

Chain OUTPUT (policy ACCEPT 170 packets, 28112 bytes)
 pkts bytes target     prot opt in     out     source               destination