Проект юного DevOps Глава 3: Настройка OpenVPN

В других версиях OpenVPN процесс и особенности настройки могут отличаться от описанных в данной статье.

################################################# # 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 dh2048.pem 2048 ;dh dh2048.pem dh none  # Network topology # Should be subnet (addressing via IP) # unless Windows clients v2.0.9 and lower have to # be supported (then net30, i.e. a /30 per client) # Defaults to net30 (not recommended) ;topology subnet  # Configure server mode and supply a VPN subnet # for OpenVPN to draw client addresses from. # The server will take 10.8.0.1 for itself, # the rest will be made available to clients. # Each client will be able to reach the server # on 10.8.0.1. Comment this line out if you are # ethernet bridging. See the man page for more info. server 10.8.0.0 255.255.255.0  # Maintain a record of client <-> virtual IP address # associations in this file.  If OpenVPN goes down or # is restarted, reconnecting clients can be assigned # the same virtual IP address from the pool that was # previously assigned. ifconfig-pool-persist /var/log/openvpn/ipp.txt  # Configure server mode for ethernet bridging. # You must first use your OS's bridging capability # to bridge the TAP interface with the ethernet # NIC interface.  Then you must manually set the # IP/netmask on the bridge interface, here we # assume 10.8.0.4/255.255.255.0.  Finally we # must set aside an IP range in this subnet # (start=10.8.0.50 end=10.8.0.100) to allocate # to connecting clients.  Leave this line commented # out unless you are ethernet bridging. ;server-bridge 10.8.0.4 255.255.255.0 10.8.0.50 10.8.0.100  # Configure server mode for ethernet bridging # using a DHCP-proxy, where clients talk # to the OpenVPN server-side DHCP server # to receive their IP address allocation # and DNS server addresses.  You must first use # your OS's bridging capability to bridge the TAP # interface with the ethernet NIC interface. # Note: this mode only works on clients (such as # Windows), where the client-side TAP adapter is # bound to a DHCP client. ;server-bridge  # Push routes to the client to allow it # to reach other private subnets behind # the server.  Remember that these # private subnets will also need # to know to route the OpenVPN client # address pool (10.8.0.0/255.255.255.0) # back to the OpenVPN server. ;push "route 192.168.10.0 255.255.255.0" ;push "route 192.168.20.0 255.255.255.0"  # To assign specific IP addresses to specific # clients or if a connecting client has a private # subnet behind it that should also have VPN access, # use the subdirectory "ccd" for client-specific # configuration files (see man page for more info).  # EXAMPLE: Suppose the client # having the certificate common name "Thelonious" # also has a small subnet behind his connecting # machine, such as 192.168.40.128/255.255.255.248. # First, uncomment out these lines: ;client-config-dir ccd ;route 192.168.40.128 255.255.255.248 # Then create a file ccd/Thelonious with this line: #   iroute 192.168.40.128 255.255.255.248 # This will allow Thelonious' private subnet to # access the VPN.  This example will only work # if you are routing, not bridging, i.e. you are # using "dev tun" and "server" directives.  # EXAMPLE: Suppose you want to give # Thelonious a fixed VPN IP address of 10.9.0.1. # First uncomment out these lines: ;client-config-dir ccd ;route 10.9.0.0 255.255.255.252 # Then add this line to ccd/Thelonious: #   ifconfig-push 10.9.0.1 10.9.0.2  # Suppose that you want to enable different # firewall access policies for different groups # of clients.  There are two methods: # (1) Run multiple OpenVPN daemons, one for each #     group, and firewall the TUN/TAP interface #     for each group/daemon appropriately. # (2) (Advanced) Create a script to dynamically #     modify the firewall in response to access #     from different clients.  See man #     page for more info on learn-address script. ;learn-address ./script  # If enabled, this directive will configure # all clients to redirect their default # network gateway through the VPN, causing # all IP traffic such as web browsing and # and DNS lookups to go through the VPN # (The OpenVPN server machine may need to NAT # or bridge the TUN/TAP interface to the internet # in order for this to work properly). push "redirect-gateway def1 bypass-dhcp"  # 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 tls-auth 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-crypt ta.key # 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-GCM auth SHA256  # Enable compression on the VPN link and push the # option to the client (v2.4+ only, for earlier # versions see below) ;compress lz4-v2 ;push "compress lz4-v2"  # For compression compatible with older clients use comp-lzo # If you enable it here, you must also # enable it in the client config file. ;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 /var/log/openvpn/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         /var/log/openvpn/openvpn.log ;log-append  /var/log/openvpn/openvpn.log  # Set the appropriate level of log # file verbosity. # # 0 is silent, except for fatal errors # 4 is reasonable for general usage # 5 and 6 can help to debug connection problems # 9 is extremely verbose verb 3  # Silence repeating messages.  At most 20 # sequential messages of the same message # category will be output to the log. ;mute 20  # Notify the client that when the server restarts so it # can automatically reconnect. explicit-exit-notify 1

Значение «eth0», которое применятся в нескольких опциях — это имя интерфейса vm, который смотрит в сеть — в вашем случае он может отличаться:

nikolay@vpn:~$ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00     inet 127.0.0.1/8 scope host lo        valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000     link/ether 0a:67:45:3e:3f:03 brd ff:ff:ff:ff:ff:ff     altname enp0s3     altname ens3     inet 10.0.0.5/24 metric 100 brd 10.0.0.255 scope global dynamic eth0        valid_lft 22804sec preferred_lft 22804sec

Опция «-p» может быть задана как «udp» или «tcp» — это зависит от настроек OpenVPN (по умолчанию используется «udp»).

Опция «—dport» тоже может быть отлична от значения по умолчанию 1194 — это тоже задается в настройках OpenVPN.

############################################## # 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.justnikobird.ru 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 # certificate has the correct key usage set. # This is an important precaution to protect against # a potential attack discussed here: #  http://openvpn.net/howto.html#mitm # # To use this feature, you will need to generate # your server certificates with the keyUsage set to #   digitalSignature, keyEncipherment # and the extendedKeyUsage to #   serverAuth # EasyRSA can do this for you. remote-cert-tls server  # If a tls-auth key is used on the server # then every client must also have the key. ;tls-crypt ta.key 1  # Select a cryptographic cipher. # If the cipher option is used on the server # then you must also specify it here. # Note that v2.4 client/server will automatically # negotiate AES-256-GCM in TLS mode. # See also the data-ciphers option in the manpage cipher AES-256-GCM auth SHA256 key-direction 1  # 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

Версия на GitHub

#!/bin/bash  # активируем опцию, которая прерывает выполнение скрипта, если любая команда завершается с ненулевым статусом set -e  # проверим, запущен ли скрипт от пользователя root if [[ "${UID}" -ne 0 ]]; then   echo "You need to run this script as root!"   exit 1 fi  # проверим подключен ли репозиторий if [[ ! $(grep -rhE ^deb /etc/apt/sources.list*) == *"deb https://repo.justnikobird.ru:1111/lab focal main"* ]]; then   echo -e "Lab repo not connected!\nPlease run vm_start.sh script!\n"   exit 1 fi  # функция, которая проверяет наличие пакета в системе и в случае его отсутствия выполняет установку command_check() {   if ! command -v "$1" &>/dev/null; then     echo -e "\n====================\n$2 could not be found!\nInstalling...\n====================\n"     apt-get install -y "$3"     echo -e "\nDONE\n"   fi }  # функция, которая проверяет наличие правила в iptables и в случае отсутствия применяет его iptables_add() {   if ! iptables -C "$@" &>/dev/null; then     iptables -A "$@"   fi }  # функция, которая проверяет наличие nat-правила в iptables и в случае отсутствия применяет его iptables_nat_add() {   if ! iptables -t nat -C "$@" &>/dev/null; then     iptables -t nat -A "$@"   fi }  # функция, которая проверяет валидность пути в linux-системе path_request() {   while true; do     read -r -e -p $'\n\n'"Please input valid path to ${1}: " path     if [ -f "$path" ]; then       echo "$path"       break     fi   done }  # выполним настройке OpenVPN echo -e "\n====================\nOpenVPN server config\n===================="  while true; do   read -r -n 1 -p "Continue or Skip? (c|s) " cs   case $cs in   [Cc]*)      # установим все необходимые пакеты используя функцию command_check     systemctl restart systemd-timesyncd.service     apt-get update     command_check openvpn "Openvpn" openvpn-lab     command_check iptables "Iptables" iptables     command_check netfilter-persistent "Netfilter-persistent" iptables-persistent     command_check basename "Basename" coreutils      # проверим наличие файла /etc/sysctl.conf в системе     if [ ! -f /etc/sysctl.conf ]; then       echo "File /etc/sysctl.conf not found!"       exit 1     fi      # запросим путь до файла сертификата и перенесем его в рабочую директорию программы     server_crt=$(path_request certificate)     cp "$server_crt" /etc/openvpn/server/     server_crt_file=$(basename "$server_crt")      # запросим путь до файла ключа и перенесем его в рабочую директорию программы     server_key=$(path_request key)     cp "$server_key" /etc/openvpn/server/     server_key_file=$(basename "$server_key")      # запросим путь до файла ca-сертификата и перенесем его в рабочую директорию программы     ca_crt=$(path_request "ca certificate")     cp "$ca_crt" /etc/openvpn/server/     cp "$ca_crt" /etc/openvpn/clients_config/keys/     ca_crt_file=$(basename "$ca_crt")      cd /etc/openvpn/server/      # сгенерируем ключ для tls-crypt     openvpn --genkey --secret ta.key     cp /etc/openvpn/server/ta.key /etc/openvpn/clients_config/keys/     echo -e "\n====================\nTls-crypt-key generated /etc/openvpn/server/ta.key\n====================\n"      # внесем изменения в конфигурационный файл open-vpn     sed -r -i 's/(^ca\s).*$/\1'"$ca_crt_file"'/' /etc/openvpn/server/server.conf     sed -r -i 's/(^cert\s).*$/\1'"$server_crt_file"'/' /etc/openvpn/server/server.conf     sed -r -i 's/(^key\s).*$/\1'"$server_key_file"'/' /etc/openvpn/server/server.conf      # активируем функцию маршрутизации     echo -e "\n====================\nIp forward configing\n====================\n"     sed -i 's/#\?\(net.ipv4.ip_forward=1\s*\).*$/\1/' /etc/sysctl.conf     sysctl -p     echo -e "\nDONE\n"      # cоздадим группу nobody для корректной работы vpn-сервиса     if ! grep -q "nobody" /etc/group; then       groupadd nobody       echo -e "\n====================\nNobody group created\n====================\n"     fi      # выполним настройку openvpn     echo -e "\n====================\nOpenVPN configuration\n====================\n"      while true; do       # выведем запрос для выбора транспорта для vpn (udp или tcp)       read -r -n 3 -p $'\n'"OpenVPN protocol (tcp|udp) (default udp): " proto       case $proto in       tcp)         # в случае выбора tcp внесем настройки в конфигурационные файлы openvpn         sed -r -i 's/(^proto\sudp$)/\;\1/' /etc/openvpn/server/server.conf         sed -r -i 's/^\;(proto\stcp$)/\1/' /etc/openvpn/server/server.conf         sed -r -i 's/(^proto\sudp$)/\;\1/' /etc/openvpn/clients_config/confiles/base.conf         sed -r -i 's/^\;(proto\stcp$)/\1/' /etc/openvpn/clients_config/confiles/base.conf         sed -r -i 's/(^explicit-exit-notify\s1$)/\;\1/' /etc/openvpn/server/server.conf         break         ;;       udp)         # в случае выбора udp вносить изменения не нужно, так как udp настроен по умолчанию         break         ;;       *) echo -e "\nPlease answer tcp or udp!\n" ;;       esac     done      # запросим у оператора ввести порт, через который будет работать openvpn     while true; do       read -r -n 4 -p $'\n\n'"OpenVPN port number (default 1194): " port       re='^[0-9]+$'       if ! [[ $port =~ $re ]]; then         echo "error: Not a number" >&2         exit 1       else         if [ "$port" == 1194 ]; then           break         else           # в случае если порт отличается от 1194, внесем изменения в конфигурационный файл           sed -r -i 's/(^port\s).*$/\1'"$port"'/' /etc/openvpn/server/server.conf           sed -r -i 's/(^port\s).*$/\1'"$port"'/' /etc/openvpn/clients_config/confiles/base.conf           break         fi       fi     done      echo -e "\n"     ip a     echo -e "\n"      # запросим hostname или ip openvpn сервера и занесем в конфигурационный файл     read -r -p $'\n'"The hostname or IP of the server: " host     sed -r -i 's/(^remote\s).*$/\1'"$host"' '"$port"'/' /etc/openvpn/clients_config/confiles/base.conf      echo -e "\n====================\nIptables configuration\n====================\n"      # запросим имя vpn-интерфейса для настройки iptables     while true; do       read -r -p $'\n'"VPN interface name: " eth       if ! ip a | grep -q "$eth"; then         echo -e "\nWrong interface name!\n"       else         break       fi     done      # выполним настройку iptables     # OpenVPN     iptables_add INPUT -i "$eth" -m state --state NEW -p "$proto" --dport "$port" -j ACCEPT -m comment --comment openvpn     # Allow TUN interfaces connections to OpenVPN server     iptables_add INPUT -i tun+ -j ACCEPT -m comment --comment openvpn     # Allow TUN interfaces connections to be forwarded through interfaces     iptables_add FORWARD -i tun+ -j ACCEPT -m comment --comment openvpn     iptables_add FORWARD -i tun+ -o "$eth" -m state --state RELATED,ESTABLISHED -j ACCEPT -m comment --comment openvpn     iptables_add FORWARD -i "$eth" -o tun+ -m state --state RELATED,ESTABLISHED -j ACCEPT -m comment --comment openvpn     # NAT the VPN client traffic to the interface     iptables_nat_add POSTROUTING -s 10.8.0.0/24 -o "$eth" -j MASQUERADE -m comment --comment openvpn     echo -e "\n====================\nSaving iptables config\n====================\n"     service netfilter-persistent save     echo -e "\nDONE\n"      # перезагрузим сервис openvpn     echo -e "\n====================\nRestarting Open-VPN service...\n====================\n"     systemctl restart openvpn-server@server.service     systemctl enable openvpn-server@server.service     echo -e "\nDONE\n"     break     ;;   [Ss]*)     echo -e "\n"     break     ;;   *) echo -e "\nPlease answer C or S!\n" ;;   esac done  # выполним настройку клиентского конфигурационного файла echo -e "\n====================\nCreate OpenVPN client config-file\n===================="  while true; do   read -r -n 1 -p "Continue or Skip? (c|s) " cs   case $cs in   [Cc]*)     # запросим клиентский сертификат и перенесем в рабочую директорию программы     client_crt=$(path_request "client certificate")     cp "$client_crt" /etc/openvpn/clients_config/keys/     client_crt_file=$(basename "$client_crt")      # запросим клиентский ключ и перенесем в рабочую директорию программы     client_key=$(path_request "client key")     cp "$client_key" /etc/openvpn/clients_config/keys/     client_key_file=$(basename "$client_key")      # запустим скрипт для генерации клиентского конфигурационного файла     read -r -p $'\n'"Client name: " client_name     if /etc/openvpn/clients_config/make_config.sh "$client_crt_file" "$client_key_file" "$client_name"; then       echo -e "\nDONE!\n\nCheck file /etc/openvpn/clients_config/${client_name}.ovpn"     fi     break     ;;    [Ss]*)     echo -e "\n"     break     ;;   *) echo -e "\nPlease answer C or S!\n" ;;   esac done  echo -e "\nOK\n" exit 0