Centos 7 安装 l2tp/ipsec

1.安装 l2tp ipsec 所需要的软件包

yum install epel-release
yum install openswan xl2tpd ppp lsof

2.设置ipsec

a.编辑 /etc/ipsec.conf(把下面xx.xxx.xxx.xxx换成你自己主机实际的外网固定IP。其他的不动。)

config setup
    protostack=netkey
    dumpdir=/var/run/pluto/
    nat_traversal=yes
    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,%v4:100.64.0.0/10,%v6:fd00::/8,%v6:fe80::/10
conn L2TP-PSK-NAT
    rightsubnet=vhost:%priv
    also=L2TP-PSK-noNAT
conn L2TP-PSK-noNAT
    authby=secret
    pfs=no
    auto=add
    keyingtries=3
    dpddelay=30
    dpdtimeout=120
    dpdaction=clear
    rekey=no
    ikelifetime=8h
    keylife=1h
    type=transport
    left=xxx.xxx.xxx.xxx      
    leftprotoport=17/1701
    right=%any
    rightprotoport=17/%any

b.编辑/etc/ipsec.secrets

include /etc/ipsec.d/*.secrets
xx.xxx.xxx.xxx %any: PSK "ZXkj8888"

xx.xxx.xxx.xxx换成你自己VPS实际的外网固定IP, YourPsk你自己定一个，到时候连VPN的时候用,就是预共享密钥，比如可以填csdn.net, 注意空格。

c.修改/添加 /etc/sysctl.conf(sysctl -p)

net.ipv4.ip_forward = 1
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.eth0.rp_filter = 0
net.ipv4.conf.default.rp_filter = 0

d.验证ipsec运行状态

ipsec setup start
ipsec verify

[root@localhost ~]# ipsec setup start
Redirecting to: systemctl start ipsec.service
[root@localhost ~]# ipsec verify
Verifying installed system and configuration files

Version check and ipsec on-path                       [OK]
Libreswan 3.15 (netkey) on 3.10.0-514.el7.x86_64
Checking for IPsec support in kernel                  [OK]
 NETKEY: Testing XFRM related proc values
         ICMP default/send_redirects                  [OK]
         ICMP default/accept_redirects                [OK]
         XFRM larval drop                             [OK]
Pluto ipsec.conf syntax                               [OK]
Hardware random device                                [N/A]
Two or more interfaces found, checking IP forwarding    [OK]
Checking rp_filter                                    [ENABLED]
 /proc/sys/net/ipv4/conf/all/rp_filter                [ENABLED]
 /proc/sys/net/ipv4/conf/ens160/rp_filter             [ENABLED]
 /proc/sys/net/ipv4/conf/ip_vti0/rp_filter            [ENABLED]
  rp_filter is not fully aware of IPsec and should be disabled
Checking that pluto is running                        [OK]
 Pluto listening for IKE on udp 500                   [OK]
 Pluto listening for IKE/NAT-T on udp 4500            [OK]
 Pluto ipsec.secret syntax                            [OK]
Checking 'ip' command                                 [OK]
Checking 'iptables' command                           [OK]
Checking 'prelink' command does not interfere with FIPSChecking for obsolete ipsec.conf options              [OK]
Opportunistic Encryption                              [DISABLED]

ipsec verify: encountered 7 errors - see 'man ipsec_verify' for help

3.设置 l2tp

a.编辑 /etc/xl2tpd/xl2tpd.conf

[global]
ipsec saref = yes
listen-addr = xxx.xxx.xxx.xxx     #这里是你的主机外网ip地址

[lns default]
ip range = 10.60.10.235-10.60.10.240
local ip = 10.60.10.1
require chap = yes
refuse pap = yes
require authentication = yes
name = LinuxVPNserver
ppp debug = yes
pppoptfile = /etc/ppp/options.xl2tpd
length bit = yes

b.编辑 /etc/ppp/options.xl2tpd

name l2tpd
require-mschap-v2
ms-dns 8.8.8.8
ms-dns 8.8.4.4
ipcp-accept-local
ipcp-accept-remote
#ms-dns  8.8.8.8
noccp
auth
crtscts
idle 1800
mtu 1410
mru 1410
nodefaultroute
debug
lock
proxyarp
connect-delay 5000

c.配置用户名,密码:编辑 /etc/ppp/chap-secrets

# Secrets for authentication using CHAP
# client        server  secret                  IP addresses
#
"linwj" * "123456" *

systemctl start xl2tpd.service     //开启L2TP服务，可观察日志：/var/log/messages

4.Windows下设置VPN连接客户端

 5.防火墙设置

/sbin/iptables -F INPUT
/sbin/iptables -Z INPUT
/sbin/iptables -P INPUT ACCEPT
/sbin/iptables -A INPUT -m state --state INVALID -j DROP
/sbin/iptables -A INPUT -p icmp -j ACCEPT
/sbin/iptables -A INPUT -i lo -j ACCEPT
/sbin/iptables -A INPUT -p tcp -m state --state NEW,RELATED,ESTABLISHED -m tcp --dport 22 -j ACCEPT
/sbin/iptables -A INPUT -p tcp -m state --state NEW,RELATED,ESTABLISHED -m tcp --dport 80 -j ACCEPT
/sbin/iptables -A INPUT -p tcp -m state --state NEW,RELATED,ESTABLISHED -m tcp --dport 1723 -j ACCEPT
/sbin/iptables -A INPUT -p gre -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT
/sbin/iptables -A INPUT -p udp -m policy --dir in --pol ipsec -m udp --dport 1701 -j ACCEPT
/sbin/iptables -A INPUT -p udp -m udp --dport 1701 -j ACCEPT
/sbin/iptables -A INPUT -p udp -m udp --dport 500 -j ACCEPT
/sbin/iptables -A INPUT -p udp -m udp --dport 4500 -j ACCEPT
/sbin/iptables -A INPUT -p esp -j ACCEPT
/sbin/iptables -A INPUT -m policy --dir in --pol ipsec -j ACCEPT
/sbin/iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
/sbin/iptables -A INPUT -j REJECT --reject-with icmp-host-prohibited
/sbin/iptables -F FORWARD
/sbin/iptables -Z FORWARD
/sbin/iptables -P FORWARD ACCEPT
/sbin/iptables -A FORWARD -m state --state INVALID -j DROP
#/sbin/iptables -A FORWARD -m policy --dir in --pol ipsec -j ACCEPT
/sbin/iptables -A FORWARD -d 10.60.10.0/24 -j ACCEPT
/sbin/iptables -A FORWARD -s 10.60.10.0/24 -j ACCEPT
/sbin/iptables -A FORWARD -i ppp+ -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT
/sbin/iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
/sbin/iptables -A FORWARD -j REJECT --reject-with icmp-host-prohibited
/sbin/iptables -F OUTPUT
/sbin/iptables -Z OUTPUT
/sbin/iptables -P OUTPUT ACCEPT
/sbin/iptables -A OUTPUT -m state --state INVALID -j DROP
/sbin/iptables -F -t nat
/sbin/iptables -Z -t nat
/sbin/iptables -t nat -A POSTROUTING -s 10.0.10.0/24 -o ens160 -j MASQUERADE

上网设置：

iptables -t nat -A POSTROUTING -s 192.168.34.0/24 -j SNAT --to-source xxx.xxx.xxx.xxx

其中10.60.10.0/24为xl2tp设置的Ip范围，—to-source为外网ip

保存配置:

iptables-save