06月16, 2018

Centos7.x 安装Openvpn详解

软件版本

  • Centos - 7.x
  • easy-rsa - 3.0.3
  • OpenVPN - 2.4.6

安装

建议安装启用epel源,采用yum的方式安装openvpn

yum install -y epel-release 
yum update -y
yum install -y openssl lzo pam openssl-devel lzo-devel pam-devel
yum install -y easy-rsa
yum install -y openvpn

使用路由还是桥接?

建议使用路由,除非你有一些需要桥接的特定场景,例如:

  • VPN需要能够处理非ip协议,如IPX
  • 通过VPN运行应用程序,该VPN依赖于网络广播(如局域网游戏)
  • 希望允许跨VPN浏览Windows文件共享,而无需设置Samba或WINS服务器

确定私有子网

Server 与 Client 的VPN通道子网,不要与已有环境的网络冲突即可。

默认:10.8.0.0/16

配置证书密钥

我们通过yum方式安装的 easy-rsa 版本是3.x,直接从安装路径copy一份工具出来。这里用默认的 easy-rsa 3.x 来配置生成证书密钥。

cp -rf /usr/share/easy-rsa/3.0.3 /etc/openvpn/server/easy-rsa
cd /etc/openvpn/server/easy-rsa

./easyrsa init-pki
./easyrsa build-ca nopass
./easyrsa build-server-full server nopass
./easyrsa build-client-full client1 nopass
./easyrsa build-client-full client2 nopass
./easyrsa gen-dh

openvpn --genkey --secret ta.key

补充:easy-rsa 2.x 执行方式(下载地址

. ./vars
./clean-all
./build-ca
./build-key-server server
./build-key client1
./build-key client2
./build-dh

openvpn --genkey --secret ta.key

配置 Server 端

创建使用的目录

# 日志存放目录
mkdir -p /var/log/openvpn/
# 用户管理目录
mkdir -p /etc/openvpn/server/user
# 配置权限
chown openvpn:openvpn /var/log/openvpn

创建Server配置文件

编辑/etc/openvpn/server/server.conf文件,并写入以下内容:

#################################################
# This file is for the server side              #
# of a many-clients <-> one-server              #
# OpenVPN configuration.                        #
#                                               #
# Comments are preceded with '#' or ';'         #
#################################################

port 1194
proto tcp-server
## Enable the management interface
# management-client-auth
# management localhost 7505 /etc/openvpn/user/management-file
dev tun     # TUN/TAP virtual network device
user openvpn
group openvpn

ca /etc/openvpn/server/easy-rsa/pki/ca.crt
cert /etc/openvpn/server/easy-rsa/pki/issued/server.crt
key /etc/openvpn/server/easy-rsa/pki/private/server.key
dh /etc/openvpn/server/easy-rsa/pki/dh.pem

tls-auth /etc/openvpn/server/easy-rsa/ta.key 0
## Using System user auth.
# plugin /usr/lib64/openvpn/plugins/openvpn-plugin-auth-pam.so login
## Using Script Plugins
auth-user-pass-verify /etc/openvpn/server/user/checkpsw.sh via-env
script-security 3

# client-cert-not-required  # Deprecated option
verify-client-cert
username-as-common-name
## Connecting clients to be able to reach each other over the VPN.
client-to-client

## Allow multiple clients with the same common name to concurrently connect.
duplicate-cn
# client-config-dir /etc/openvpn/server/ccd
# ifconfig-pool-persist ipp.txt

server 10.8.0.0 255.255.255.0
push "dhcp-option DNS 114.114.114.114"
push "dhcp-option DNS 1.1.1.1"
push "route 10.93.0.0 255.255.255.0"

# comp-lzo - DEPRECATED This option will be removed in a future OpenVPN release. Use the newer --compress instead.
compress lzo
# cipher AES-256-CBC
ncp-ciphers "AES-256-GCM:AES-128-GCM"
## In UDP client mode or point-to-point mode, send server/peer an exit notification if tunnel is restarted or OpenVPN process is exited.
# explicit-exit-notify 1
keepalive 10 120
persist-key
persist-tun
verb 3

log /var/log/openvpn/server.log
log-append /var/log/openvpn/server.log
status /var/log/openvpn/status.log

注意!!! 这里创建完配置文件后,需要做个配置文件的软连接,因为当前版本的 openvpn systemd 启动文件中读取的是.service.conf配置。

cd /etc/openvpn/server/
ln -sf server.conf .service.conf

创建用户密码文件

格式是用户 密码以空格分割即可

tee /etc/openvpn/server/user/psw-file << EOF
mytest mytestpass
EOF

chmod 600 /etc/openvpn/server/user/psw-file
chown openvpn:openvpn /etc/openvpn/server/user/psw-file

创建密码检查脚本

#!/bin/sh
###########################################################
# checkpsw.sh (C) 2004 Mathias Sundman <mathias@openvpn.se>
#
# This script will authenticate OpenVPN users against
# a plain text file. The passfile should simply contain
# one row per user with the username first followed by
# one or more space(s) or tab(s) and then the password.

PASSFILE="/etc/openvpn/server/user/psw-file"
LOG_FILE="/var/log/openvpn/password.log"
TIME_STAMP=`date "+%Y-%m-%d %T"`
###########################################################
if [ ! -r "${PASSFILE}" ]; then
  echo "${TIME_STAMP}: Could not open password file \"${PASSFILE}\" for reading." >>  ${LOG_FILE}
  exit 1
fi
CORRECT_PASSWORD=`awk '!/^;/&&!/^#/&&$1=="'${username}'"{print $2;exit}' ${PASSFILE}`
if [ "${CORRECT_PASSWORD}" = "" ]; then
  echo "${TIME_STAMP}: User does not exist: username=\"${username}\", password=

\"${password}\"." >> ${LOG_FILE}
  exit 1
fi
if [ "${password}" = "${CORRECT_PASSWORD}" ]; then
  echo "${TIME_STAMP}: Successful authentication: username=\"${username}\"." >> ${LOG_FILE}
  exit 0
fi

echo "${TIME_STAMP}: Incorrect password: username=\"${username}\", password=

\"${password}\"." >> ${LOG_FILE}
exit 1

防火墙配置

firewall-cmd --permanent --add-masquerade
firewall-cmd --permanent --add-service=openvpn
# 或者添加自定义端口
# firewall-cmd --permanent  --add-port=1194/tcp
firewall-cmd --permanent --direct --passthrough ipv4 -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE
firewall-cmd --reload

启动服务

# 查看service名
rpm -ql openvpn |grep service
/usr/lib/systemd/system/openvpn-client@.service
/usr/lib/systemd/system/openvpn-server@.service
/usr/lib/systemd/system/openvpn@.service

# 启动
systemctl start openvpn-server@.service.service

配置客户端

从server上将生成的ca.crtclient1.crtclient1.keyta.key文件下载到客户端,客户端配置内容C:\Program Files\OpenVPN\config\client.ovpn如下:

# 
client
proto tcp-client
dev tun
auth-user-pass
remote yourserver.domain 1194

ca ca.crt
cert client1.crt
key client1.key
tls-auth ta.key 1

remote-cert-tls server
auth-nocache
persist-tun
persist-key
compress lzo
verb 4
mute 10

本文链接:https://fandenggui.com/post/centos7-install-openvpn.html

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