第一部分：安装L2TP:
wget --no-check-certificate https://raw.githubusercontent.com/teddysun/across/master/l2tp.sh
chmod +x l2tp.sh
./l2tp.sh
第二部分：安装freeradius-client
下载，解压，编译安装freeadius：
wget ftp://ftp.freeradius.org/pub/freeradius/freeradius-client-1.1.7.tar.gz
tar -zxvf freeradius-client-1.1.7.tar.gz
./configure
make && make install
参数配置：
vi /usr/local/etc/radiusclient/servers
加入：验证服务器ip 密钥
120.25.78.232 klink
vi /usr/local/etc/radiusclient/radiusclient.conf
内容写入：
auth_order radius,local
login_tries 4
login_timeout 60
nologin /etc/nologin
issue /usr/local/etc/radiusclient/issue
authserver 验证服务器:1812
acctserver 验证服务器:1813
servers /usr/local/etc/radiusclient/servers
dictionary /usr/local/etc/radiusclient/dictionary
login_radius /usr/sbin/login.radius
seqfile /var/run/radius.seq
mapfile /usr/local/etc/radiusclient/port-id-map
default_realm
radius_timeout 10
radius_retries 3
login_local /bin/login
Bash
vi /usr/local/etc/radiusclient/dictionary
在最后加入：
INCLUDE /usr/local/etc/radiusclient/dictionary.microsoft
INCLUDE /usr/local/etc/radiusclient/dictionary.ascend
INCLUDE /usr/local/etc/radiusclient/dictionary.compat
INCLUDE /usr/local/etc/radiusclient/dictionary.merit
vi /etc/ppp/options.xl2tpd
在最后加入：
plugin radius.so
plugin radattr.so
radius-config-file /usr/local/etc/radiusclient/radiusclient.conf
重启服务：
service xl2tpd restart
清空日志：
cat /dev/null > /var/log/messages
尝试使用帐号登陆，出现错误则打开日志，查看错误，注释相应错误：
vi /var/log/messages
//dictionary.microsoft 需要上传到服务器对应位置
//dictionary 为修正版适用于vr云主机