| L2TP是一種工業標准的Internet隧道協議，功能大致和PPTP協議類似，比如同樣可以對網絡數據流進行加密。不過也有不同之處，比如PPTP要求網絡為IP網絡，L2TP要求面向數據包的點對點連接；PPTP使用單一隧道，L2TP使用多隧道；L2TP提供包頭壓縮、隧道驗證，而PPTP不支持。本文來介紹如何搭建L2TP。 |
1.先看看你的主機是否支持pptp，返回結果為yes就表示通過
modprobe ppp-compress-18 && echo yes
2.是否開啟了TUN
有的虛擬機主機需要開啟，返回結果為cat: /dev/net/tun: File descriptor in bad state。就表示通過。
cat /dev/net/tun
3.更新一下再安裝
yum install update yum update -y
4.安裝EPEL源
yum install -y epel-release
5.安裝xl2tpd和libreswan
yum install -y xl2tpd libreswan lsof
6.編輯xl2tpd配置文件
vim /etc/xl2tpd/xl2tpd.conf
修改內容如下：
[global] [lns default] ip range = 172.100.1.100-172.100.1.150 #分配給客戶端的地址池 local ip = 172.100.1.1 require chap = yes refuse pap = yes require authentication = yes name = LinuxVPNserver ppp debug = yes pppoptfile = /etc/ppp/options.xl2tpd length bit = yes
7.編輯pppoptfile文件
vim /etc/ppp/options.xl2tpd
修改內容如下：
ipcp-accept-local ipcp-accept-remote ms-dns 8.8.8.8 ms-dns 209.244.0.3 ms-dns 208.67.222.222 name xl2tpd #noccp auth crtscts idle 1800 mtu 1410 #第一次配置不建議設置mtu，mru，否則可能789錯誤 mru 1410 nodefaultroute debug lock proxyarp connect-delay 5000 refuse-pap refuse-chap refuse-mschap require-mschap-v2 persist logfile /var/log/xl2tpd.log
8.編輯ipsec配置文件
vim /etc/ipsec.conf
config setup
protostack=netkey
dumpdir=/var/run/pluto/
virtual_private=%v4:10.0.0.0/8,%v4:172.100.0.0/12,%v4:25.0.0.0/8,%v4:100.64.0.0/10,%v6:fd00::/8,%v6:fe80::/10
include /etc/ipsec.d/*.conf
9.編輯include的conn文件
vim /etc/ipsec.d/l2tp-ipsec.conf
修改內容如下：
conn L2TP-PSK-NAT
rightsubnet=0.0.0.0/0
dpddelay=10
dpdtimeout=20
dpdaction=clear
forceencaps=yes
also=L2TP-PSK-noNAT
conn L2TP-PSK-noNAT
authby=secret
pfs=no
auto=add
keyingtries=3
rekey=no
ikelifetime=8h
keylife=1h
type=transport
left=192.168.0.17 #service/VPS的外網地址，某些vps只有eth0一塊網卡的，
#就填內網地址，內核開啟nat轉發就可以了，
#CentOS7以下的用iptables定義轉發規則
leftprotoport=17/1701
right=%any
rightprotoport=17/%any
10.設置用戶名密碼
vim /etc/ppp/chap-secrets
修改內容：
vpnuser * pass * 說明：用戶名[空格]service[空格]密碼[空格]指定IP
11.設置PSK
vim /etc/ipsec.d/default.secrets
: PSK "testvpn"
12.CentOS7防火牆設置
firewall-cmd --permanent --add-service=ipsec firewall-cmd --permanent --add-port=1701/udp firewall-cmd --permanent --add-port=4500/udp firewall-cmd --permanent --add-masquerade firewall-cmd --reload
13.IP_FORWARD 設置
vim /etc/sysctl.d/60-sysctl_ipsec.conf
net.ipv4.ip_forward = 1 net.ipv4.conf.all.accept_redirects = 0 net.ipv4.conf.all.rp_filter = 0 net.ipv4.conf.all.send_redirects = 0 net.ipv4.conf.default.accept_redirects = 0 net.ipv4.conf.default.rp_filter = 0 net.ipv4.conf.default.send_redirects = 0 net.ipv4.conf.eth0.accept_redirects = 0 net.ipv4.conf.eth0.rp_filter = 0 net.ipv4.conf.eth0.send_redirects = 0 net.ipv4.conf.eth1.accept_redirects = 0 net.ipv4.conf.eth1.rp_filter = 0 net.ipv4.conf.eth1.send_redirects = 0 net.ipv4.conf.eth2.accept_redirects = 0 net.ipv4.conf.eth2.rp_filter = 0 net.ipv4.conf.eth2.send_redirects = 0 net.ipv4.conf.ip_vti0.accept_redirects = 0 net.ipv4.conf.ip_vti0.rp_filter = 0 net.ipv4.conf.ip_vti0.send_redirects = 0 net.ipv4.conf.lo.accept_redirects = 0 net.ipv4.conf.lo.rp_filter = 0 net.ipv4.conf.lo.send_redirects = 0 net.ipv4.conf.ppp0.accept_redirects = 0 net.ipv4.conf.ppp0.rp_filter = 0 net.ipv4.conf.ppp0.send_redirects = 0
重啟生效
systemctl restart network
13.ipsec啟動&檢查
systemctl enable ipsec systemctl restart ipsec
檢查：ipsec verify
正常輸出：
Verifying installed system and configuration files
Version check and ipsec on-path [OK]
Libreswan 3.15 (netkey) on 3.10.0-123.13.2.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 [OK]
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]
14.xl2tpd啟動
systemctl enable xl2tpd systemctl restart xl2tpd
15.Windows連接
Windows連接，需要修改注冊表鍵值（據說可以不用修改，但是我的不修改的話，一直789，log無顯示）