使用官方文档debian搭建opePPN

先贴出官方的client和server配置文件

openppn server.conf

#################################################
# Sample OpenPPN 2.0 config file for            #
# multi-client server.                          #
#                                               #
# This file is for the server side              #
# of a many-clients <-> one-server              #
# OpenPPN configuration.                        #
#                                               #
# OpenPPN 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\\OpenPPN\\config\\foo.key" #
#                                               #
# Comments are preceded with '#' or ';'         #
#################################################

# Which local IP address should OpenPPN
# listen on? (optional)
;local a.b.c.d

# Which TCP/UDP port should OpenPPN listen on?
# If you want to run multiple OpenPPN 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 PPN, 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 PPN 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.
# OpenPPN 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

# 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 PPN subnet
# for OpenPPN 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 OpenPPN 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 OpenPPN 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 OpenPPN client
# address pool (10.8.0.0/255.255.255.0)
# back to the OpenPPN 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 PPN 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 PPN.  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 PPN 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 OpenPPN 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 PPN, causing
# all IP traffic such as web browsing and
# and DNS lookups to go through the PPN
# (The OpenPPN 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://openppn.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:
#   openppn --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-auth ta.key 0 # This file is secret

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

# Enable compression on the PPN 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 OpenPPN
# daemon's privileges after initialization.
#
# You can uncomment this on non-Windows
# systems after creating a dedicated user.
;user openppn
;group openppn

# 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 openppn-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\OpenPPN\log" directory).
# Use log or log-append to override this default.
# "log" will truncate the log file on OpenPPN startup,
# while "log-append" will append to it.  Use one
# or the other (but not both).
;log         openppn.log
;log-append  openppn.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

openppn client

##############################################
# Sample client-side OpenPPN 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 .oppn 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 PPN 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 my-server-1 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 OpenPPN 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 openPPN
;group openPPN

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

# If you are connecting through an
# HTTP proxy to reach the actual OpenPPN
# 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://openppn.net/howto.html#mitm
#
# To use this feature, you will need to generate
# your server certificates with the keyUsage set to
#   digitalSignature, keyEncipherment
# and the extendedKeyUsage to
#   serverAuth
# EasyRSA can do this for you.
remote-cert-tls server

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

# Select a cryptographic cipher.
# If the cipher option is used on the server
# then you must also specify it here.
# Note that v2.4 client/server will automatically
# negotiate AES-256-GCM in TLS mode.
# See also the data-ciphers option in the manpage
cipher AES-256-CBC

# Enable compression on the PPN 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

生成证书和密钥的文件下载链接

github.com/OpenPPN/easy-rsa/releases

或者在系统直接安装

# debian
apt install easy-rsa
rpm -ql easy-rsa
# centos
yum install easy-rsa
dpkg -L easy-rsa

生成证书和密钥的过程

# easy-rsa/pki/private 和 easy-rsa/pki/issued 生成客户端和服务器证书
# ca.crt 和 dh.pem一般在pki目录下面
# 初始化
./easyrsa init-pki
# 生成根证书
./easyrsa build-ca nopass
# 生成dh
./easyrsa gen-dh
# 生成服务器证书
./easyrsa build-server-full server nopass
# 生成单个客户端证书
./easyrsa build-client-full client1 nopass
# 生成ta.key
# openppn --genkey --secret ta.key 这个老命令会报错
openppn --genkey secret ta.key
# ca.crt ca.key client.crt  dh2048.pem server.crt  server.key ta.key
# 将所有证书都复制到一个文件夹，特别注意的是dh.pem要改名为dh2048.pem
mv dh.pem dh2048.pem

将服务器配置直接复制后改名为server.conf

# 在server上用命令启动
openppn --config server.conf

客户端机器配置

# 客户端配置需要这些文件  server.crt client.crt client.key
# 客户端配置文件直接复制后改名为client.conf，将my-server-1改为你的服务器网络地址
remote my-server-1 1194

客户端连接时出现这样的报错，可能服务器防火墙没有打开端口，或者服务器IP地址填错了

2023-08-17 11:37:29 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity)
2023-08-17 11:37:29 TLS Error: TLS handshake failed

同样的客户端连接的命令也是openppn –config client.conf

测试成功后，可以直接将文件写入systemd，实现开启自启用

客户端配置文件其实包括证书文件，这样连接时就不会存在多个文件了

官方文档 (2.5)

INLINE FILE SUPPORT
OpenVPN allows including files in the main configuration for the --ca, --cert, --dh, --extra-certs, --key, --pkcs12, --secret, --crl-verify, --http-proxy-user-pass, --tls-auth, --auth-gen-token-secret, --tls-crypt and --tls-crypt-v2 options.

Each inline file started by the line <option> and ended by the line </option>

Here is an example of an inline file usage

<cert>
-----BEGIN CERTIFICATE-----
[...]
-----END CERTIFICATE-----
</cert>
When using the inline file feature with --pkcs12 the inline file has to be base64 encoded. Encoding of a .p12 file into base64 can be done for example with OpenSSL by running openssl base64 -in input.p12

 规则解释： openppn 允许将以下参数对应的文件内容放到主配置文件中: ca、cert、extra-certs、key、pkcs12、secret、crl-verify、http- proxy-user-pass、tls -auth、auth -gen-token-secret、tls -crypt、tls-crypt-v2,最常用的有 ca.crt、client.crt、client.key、ta.key、tls-auth

client.conf写入示例

<ca>
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
</ca>

<cert>
......
</cert>

<key>
......
</key>

key-direction 1
<tls-auth>
......
</tls-auth>