一、环境准备
1.服务器
查看系统版本
cat /etc/redhat-release
操作系统：CentOS Linux release 7.7.1908 (Core)
IP地址：122.51.8.56
2、客户端
windows10操作系统，手机端
二、服务器配置
1、确定内核是否支持mppe
modprobe ppp-compress-18 && echo good!
如果输出good！，那么支持mppe，否则需要升级内核支持mppe，自行百度。
2、检查ppp是否开启
cat /dev/ppp
3、安装ppp和pptpd
yum install ppp && yum install pptpd
4、编写配置文件
客户端分配的内网ip段
vi /etc/
将#号去掉，或自行配置
配置dns
vi /etc/ppp/
这里我用的是谷歌的dns，可以有两个，第二个是备用的，自行选择。
修改日志记录 ，方便查找错误(在文件最后)
5、添加用户登录的用户名及密码
vi /etc/ppp/chap-secrets
格式为
用户名 pptpd 密码 * 中间用tab键隔开
6、修改内核参数，使服务器可以转发
vi /etc/
将net.ipv4.ip_forward=0修改为1，保存退出
sysctl -p#使内核参数生效
7.添加iptables转发规则
iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -o eth0 -j MASQUERADE
重启后会失效，修改/etc//保存上面的命令，这样开机会自动执行上面的命令。
8.开机自启
chkconfig pptpd on#开机自启
systemctl restart pptpd#重启
三、使用
使用win10自带的，或者手机自带的尝试连接，但是一直没有成功。
并且日志一直报这个错误。
Plugin /usr/lib64/pptpd/ loaded.
pptpd-logwtmp: $Version$
pppd options in effect:
debug # (from /etc/ppp/)
logfile /var/log/ # (from /etc/ppp/)
dump # (from /etc/ppp/)
plugin /usr/lib64/pptpd/ # (from command line)
require-mschap-v2 # (from /etc/ppp/)
refuse-pap # (from /etc/ppp/)
refuse-chap # (from /etc/ppp/)
refuse-mschap # (from /etc/ppp/)
name pptpd # (from /etc/ppp/)
remotenumber 117.136.92.127 # (from command line)
pptpd-original-ip 117.136.92.127 # (from command line)
115200 # (from command line)
lock # (from /etc/ppp/)
local # (from command line)
novj # (from /etc/ppp/)
novjccomp # (from /etc/ppp/)
ipparam 117.136.92.127 # (from command line)
ms-dns xxx # [don't know how to print value] # (from /etc/ppp/)
proxyarp # (from /etc/ppp/)
192.168.0.1:192.168.0.234 # (from command line)
nobsdcomp # (from /etc/ppp/)
require-mppe-128 # (from /etc/ppp/)
using channel 22
Using interface ppp0
Connect: ppp0 /dev/pts/4
sent [LCP ConfReq id=0x1 ]
sent [LCP ConfReq id=0x1 ]
sent [LCP ConfReq id=0x1 ]
sent [LCP ConfReq id=0x1 ]
sent [LCP ConfReq id=0x1 ]
sent [LCP ConfReq id=0x1 ]
sent [LCP ConfReq id=0x1 ]
sent [LCP ConfReq id=0x1 ]
sent [LCP ConfReq id=0x1 ]
sent [LCP ConfReq id=0x1 ]
LCP: timeout sending Config-Requests
Connection terminated.
Modem hangup
