【已解决】新搭建的VPN服务器客户端无法正常连接

昨天花了一天的时间，终于把VPN服务器搭建好了。
但是客户端却一直提示无法拨号成功。查看VPN日志如下：

[root@localhost log]# tail -f messages 
Jun 13 14:00:25 localhost pptpd[9248]: CTRL: Client 101.69.242.170 control connection started
Jun 13 14:00:25 localhost pptpd[9248]: CTRL: Starting call (launching pppd, opening GRE)
Jun 13 14:00:25 localhost pppd[9249]: Warning: can't open options file /root/.ppprc: Permission denied
Jun 13 14:00:25 localhost pppd[9249]: The remote system is required to authenticate itself
Jun 13 14:00:25 localhost pppd[9249]: but I couldn't find any suitable secret (password) for it to use to do so.
Jun 13 14:00:25 localhost pppd[9249]: (None of the available passwords would let it use an IP address.)
Jun 13 14:00:25 localhost pptpd[9248]: GRE: read(fd=6,buffer=6124a0,len=8196) from PTY failed: status = -1 error = Input/output error, usually caused by unexpected termination of pppd, check option syntax and pppd logs
Jun 13 14:00:25 localhost pptpd[9248]: CTRL: PTY read or GRE write failed (pty,gre)=(6,7)
Jun 13 14:00:25 localhost pptpd[9248]: CTRL: Client 101.69.242.170 control connection finished

相关配置文件

[root@localhost ~]# more /etc/pptpd.conf |grep -v ^#
option /etc/ppp/options.pptpd
debug /var/log/pptpd.log
localip 10.10.1.20
remoteip 10.10.1.30-254
[root@localhost ~]# more /etc/ppp/options.pptpd|grep -v ^#
name pptpd
refuse-pap
refuse-chap
refuse-mschap
require-mschap-v2
require-mppe-128
ms-dns 221.228.255.1
ms-dns 223.6.6.6
proxyarp
lock
nobsdcomp 
novj
novjccomp
nologfd

我使用的centos 6.5 64bit ，相关安装包如下：
[root@localhost ~]# rpm -qa |grep "ppp*"
libreport-plugin-rhtsupport-2.0.9-19.el6.centos.x86_64
device-mapper-event-libs-1.02.79-8.el6.x86_64
ppl-0.10.2-11.el6.x86_64
pptpd-1.4.0-3.el6.x86_64
abrt-addon-ccpp-2.0.8-21.el6.centos.x86_64
device-mapper-1.02.79-8.el6.x86_64
device-mapper-event-1.02.79-8.el6.x86_64
tcp_wrappers-7.6-57.el6.x86_64
cloog-ppl-0.15.7-1.2.el6.x86_64
snappy-1.1.0-1.el6.x86_64
kernel_ppp_mppe-1.0.2-3dkms.noarch
pptp-1.7.2-8.1.el6.x86_64
device-mapper-libs-1.02.79-8.el6.x86_64
tcp_wrappers-libs-7.6-57.el6.x86_64
cpp-4.4.7-4.el6.x86_64
device-mapper-persistent-data-0.2.8-2.el6.x86_64
ppp-2.4.5-5.el6.x86_64

现在不知道问题出在什么地方，麻烦各位帮忙看看，谢谢！！！
已经解决，修改配置

options.pptpd把

require-mschap-v2

require-mppe-128这两行注释掉即可。如下图：