CentOS7 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.confconfig 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.confnet.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，需要修改註冊表鍵值（據說可以不用修改，但是我的不修改的話，一直789，log無顯示）

原文地址：https://www.linuxprobe.com/centos7-install-l2tp.html

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