AWS亚马逊服务器搭建VPN

一、AWS EC2搭建L2TP/IPSec VPN服务器

AWS针对新注册的用户提供一年免费EC2服务。Amazon EC2有一定限制，一个月流量限制不超过15G。

设置提醒，防止超出限制多扣费。

关于IPsec VPN可参考：https://github.com/hwdsl2/setup-ipsec-vpn/blob/master/README-zh.md

二、AWS亚马逊服务器搭建VPN

来源：AWS亚马逊服务器搭建VPN - ACE VPN

以前在免费的亚马逊服务器上搭建过Shadowsocks程序，稳定性和速度还算不错，但也有局限性，比如 Bash终端无法翻墙搭建vpn服务器，部分不支持大理的软件无法翻墙出去，所以就打算在服务器上在搭建一个VPN。

目前可用的开源VPN服务器端有IPSec、L2TP/IPSec和PPTP。PPTP由于安全性等因素已被IOS抛弃，所以打算安装L2TP/IPSec。L2TP/IPSec的安装和Shadowsocks相比较为简单，但要使用配置起来要比Shadowsocks繁琐了很多。

安装

服务器环境：

亚马逊免费服务器 Ubuntu12.04

安装必备的软件包搭建vpn服务器，L2TP/IPSec所需要的就三个软件，命令搞定：

sudo apt-get install openswan ppp xl2tpd

配置1.修改Ipsec的配置文件

打开配置文件

sudo vim  /etc/ipsec.conf

修改配置文件

# /etc/ipsec.conf - Openswan IPsec configuration file
# This file:  /usr/share/doc/openswan/ipsec.conf-sample
#
# Manual:     ipsec.conf.5
version 2.0     # conforms to second version of ipsec.conf specification
# basic configuration
config setup
    # Do not set debug options to debug configuration issues!
    # plutodebug / klipsdebug = "all", "none" or a combation from below:
    # "raw crypt parsing emitting control klips pfkey natt x509 dpd private"
    # eg:
    # plutodebug="control parsing"
    # Again: only enable plutodebug or klipsdebug when asked by a developer
    #
    # enable to get logs per-peer
    # plutoopts="--perpeerlog"
    #
    # Enable core dumps (might require system changes, like ulimit -C)
    # This is required for abrtd to work properly
    # Note: incorrect SElinux policies might prevent pluto writing the core
    dumpdir=/var/run/pluto/
    #
    # NAT-TRAVERSAL support, see README.NAT-Traversal
    nat_traversal=yes
    # exclude networks used on server side by adding %v4:!a.b.c.0/24
    # It seems that T-Mobile in the US and Rogers/Fido in Canada are
    # using 25/8 as "private" address space on their 3G network.
    # This range has not been announced via BGP (at least upto 2010-12-21)
    virtual_private=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%v4:172.16.0.0/12,%v4:25.0.0.0/8,%v6:fd00::/8,%v6:fe80::/10
    # OE is now off by default. Uncomment and change to on, to enable.
    oe=off
    # which IPsec stack to use. auto will try netkey, then klips then mast
    protostack=netkey
    # Use this to log to a file, or disable logging on embedded systems (like openwrt)
    #plutostderrlog=/dev/null
# Add connections here
# sample VPN connection
# for more examples, see /etc/ipsec.d/examples/
#conn sample
#               # Left security gateway, subnet behind it, nexthop toward right.
#               left=10.0.0.1
#               leftsubnet=172.16.0.0/24
#               leftnexthop=10.22.33.44
#               # Right security gateway, subnet behind it, nexthop toward left.
#               right=10.12.12.1
#               rightsubnet=192.168.0.0/24
#               rightnexthop=10.101.102.103
#               # To authorize this connection, but not actually start it, 
#               # at startup, uncomment this.
#               #auto=add
conn L2TP-PSK-NAK
     rightsubnet=vhost:%priv
     also=L2TP-PAK-noNAT
conn L2TP-PSK-noNAT
     authby=secret
     pfs=no
     auto=add
     keyingtries=3
     rekey=no
     ikelifetime=8h
     keylife=1h
     type=transport
     left=*.*.*.*(此处填服务器内网地址)
     leftprotoport=17/1701
     right=%any
     rightprotoport=17/%any
     dpddelay=40
     dpdtimeout=130
     dpdaction=clear

这份文件主要修改原来配置中的protostack=netkey

以及加入conn L2TP-PSK-NAK和conn L2TP-PSK-noNAT的配置即可，注意left=…(此处填服务器内网地址)

2.修改Ipsec的Secrets

打开配置文件

sudo vim /etc/ipsec.secrets 

修改配置文件

# This file holds shared secrets or RSA private keys for inter-Pluto
# authentication.  See ipsec_pluto(8) manpage, and HTML documentation.
# RSA private key for this host, authenticating it to any other host
# which knows the public part.  Suitable public keys, for ipsec.conf, DNS,
# or configuration of other implementations, can be extracted conveniently
# with "ipsec showhostkey".
# this file is managed with debconf and will contain the automatically created RSA keys
include /var/lib/openswan/ipsec.secrets.inc
x.x.x.x(此处填你的服务器内网地址)  %any:  PSK "预共享密钥"

⚠️这份文件x.x.x.x处改成你的服务器内网地址，PSK后修改你自己的预共享密钥(需记住)，后续连接过程中要用

3.关闭网卡部分功能

由于IPSec工作时可能会与网络接口的send_redirects和accept_redirects功能相冲突，因此需要在启动IPSec前将网卡的这些功能关闭。运行：

echo 0 > /proc/sys/net/ipv4/conf/eth0/send_redirects
echo 0 > /proc/sys/net/ipv4/conf/eth0/accept_redirects

这一步如果提示权限不足，建议 将指令写入 sh文件，sudo运行该文件即可。

touch disableeth0.sh
vim disableeth0.sh

然后写入：

#!/bin/bash
# Disable send redirects
echo 0 > /proc/sys/net/ipv4/conf/eth0/send_redirects
echo 0 > /proc/sys/net/ipv4/conf/eth0/accept_redirects  

赋予可执行权限,并执行：

chmod +x  disableeth0.sh
./disableeth0.sh

4.重启ipsec服务并检查其是否正常工作

执行

sudo service ipsec restart
sudo ipsec verify

这时候你会看到程序自检了:

Checking your system to see if IPsec got installed and started correctly:
Version check and ipsec on-path                                 [OK]
Linux Openswan U2.6.38/K3.13.0-92-generic (netkey)
Checking for IPsec support in kernel                            [OK]
SAref kernel support                                           [N/A]
NETKEY:  Testing XFRM related proc values                      [OK]
    [OK]
    [OK]
Checking that pluto is running                                  [OK]
Pluto listening for IKE on udp 500                             [OK]
Pluto listening for NAT-T on udp 4500                          [OK]
Checking for 'ip' command                                       [OK]
Checking /bin/sh is not /bin/dash                               [WARNING]
Checking for 'iptables' command                                 [OK]
Opportunistic Encryption Support                                [DISABLED]

第三项、倒数第一项和第二项不用去理会，如果你的结果和我一样了，恭喜Ipsec的配置算是完成了，如果没有请仔细检查上述配置哪边没有配好。

5.修改xl2tpd的配置文件

打开配置文件：

sudo vim /etc/xl2tpd/xl2tpd.conf

在文件末尾添加：

[global]
ipsec saref = yes
[lns default]
ip range = x.x.x.x-x.x.x.x
local ip = x.x.x.x
refuse chap = yes
refuse pap = yes
require authentication = yes
name = OpenswanVPN
ppp debug = yes
pppoptfile = /etc/ppp/options.xl2tpd
length bit = yes

其中

local ip后面x.x.x.x处改成你的服务器内网地址

ip range后面x.x.x.x-x.x.x.x处改成可使用的服务器内网ip地址段，如果你的服务器内网ip是 10.12.13.10，那此处你可填写 10.12.13.11-10.12.13.50，修改ip的末尾数字即可(不要把自己的ip段包含在内)

6.修改ppp配置文件

修改（新建）配置文件 /etc/ppp/options.xl2tpd

sudo vim /etc/ppp/options.xl2tpd

添加下列内容：

require-mschap-v2
ms-dns 8.8.8.8
ms-dns 8.8.4.4
auth
mtu 1200
mru 1000
crtscts
hide-password
modem
name l2tpd
proxyarp

7.设置vpn客户端用户名密码

由于使用ms-chap-v2认证，修改配置文件 /etc/ppp/chap-secrets

sudo vim /etc/ppp/chap-secrets

格式如下：

# client    server    secret            IP addresses
用户名       l2tpd      密码              *

其中server和IP addresses不变，其余字段用户自定义，这是客户端用来连接的用户名密码

8.开启ip转发

打开配置文件

sudo vim /etc/sysctl.conf

在文件末尾添加

net.ipv4.ip_forward = 1
net.ipv4.conf.default.rp_filter = 0
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.icmp_ignore_bogus_error_responses = 1

9.加载系统配置

命令行执行

sysctl -p

10.设置转发规则

命令行执行

iptables -t nat -A POSTROUTING -j MASQUERADE

11.（非必需）修改启动脚本

因为上述步骤，在系统重启后会被重置，因此可选在在启动脚本加入配置

打开配置文件

sudo vim /etc/rc.local

在尾端添加

iptables –table nat –append POSTROUTING –jump MASQUERADE
echo 1 > /proc/sys/net/ipv4/ip_forward
for each in /proc/sys/net/ipv4/conf/*
do
echo 0 > $each/accept_redirects
echo 0 > $each/send_redirects
done

12.重启相关服务

命令行执行

/etc/init.d/pppd-dns restart
sudo /etc/init.d/xl2tpd restart
sudo /etc/init.d/ipsec restart

13.客户端配置iphone配置如下