PPTP VPN部署好了之后，客户端的配置相对于OpenVPN的客户端相对而言就简单太多了，而且pptp无须安装客户端（Windows），而目前大部分人都使用windows客户端，因此易用性上是要优越于OpenVPN的，甚至在网上有看到有的公司就因为这一点抛弃OpenVPN而选择pptpd。当然，选择适合的VPN不能只看重这一点，而是需要综合考虑自己的业务需求以及方案的可实施性等多方面的因素，这里不多做评论。鉴于网上关于PPTPD VPN服务器端的安装教程很多，却少有讲解pptp客户端的安装使用，所以添加一下自己的使用心得，以作备用。
一、Linux客户端
要在Linux上使用pptp VPN，首先需要安装pptp和pptp-setup两个包，注意是pptp而不是服务器端的pptpd，下载对应的RPM包安装即可。
rpm -qa pptp pptp-setup #检查是否安装了pptp和pptp-setup两个包
wget ftp://rpmfind.net/linux/centos/6.8/os/x86_64/Packages/pptp-
1.7.2-8.1.el6.x86_64.rpm
rpm -ivh pptp-1.7.2-8.1.el6.x86_64.rpm
wget ftp://rpmfind.net/linux/centos/6.8/os/x86_64/Packages/pptp-
setup-1.7.2-8.1.el6.x86_64.rpm
rpm -ivh pptp-setup-1.7.2-8.1.el6.x86_64.rpm
下面看一下pptpsetup的用法：
pptpsetup --help
pptpsetup --create <TUNNEL> --server <SERVER> [--domain <DOMAIN>]
--username <USERNAME> [--password <PASSWORD>]
[--encrypt] [--start]
pptpsetup --delete <TUNNEL>
Options:
* the name you wish to use to refer to the tunnel (you choose it),
* the IP address or host name of the server,
* the authentication domain name (optional),
* the username you are to use,
* the password you are to use,
* whether encryption is required,
* whether to start the connection after configuration.
########################################################################
这里的注释是和上面的命令参数对应的，具体如下：
<TUNNEL>：指定需要创建的vpn连接的名称
<SERVER>：PPTP VPN服务器的ip地址或者主机名（如果是主机名，需要做好DNS解析，无论是公网还是本地DNS）
<DOMAIN>：验证的域名，pptp vpn初始使用chap-secret本地认证，但是也支持ldap认证，在使用ldap认证时，该项有用到
<USERNAME>：连接到vpn的用户名
<PASSWORD>：连接到vpn的用户密码
[--encrypt]：选择是否启用加密，这个也要跟服务器端一致，如果不一致，会有信息提示
[--start]：选择立即启动连接还是在创建配置完成后再启动，一般只在第一次创建vpn连接时使用
########################################################################
pptpsetup - Point-to-Point Tunneling Protocol setup
Copyright (C) 2006 Nelson Ferraz
pptpsetup comes with ABSOLUTELY NO WARRANTY; for details see source.
This is free software, and you are welcome to redistribute it
under certain conditions; see source for details.
根据上面给出的使用帮助，如果我们想要新创建一个vpn连接，命令如下：
pptpsetup --create vpn --server --username test -
-password 123456 --encrypt
创建完成后，如果以后需要调用它，只需要执行以下命令即可。
pppd call vpn
[[email protected] ~]# pptpsetup --create vpn --server 192.168.49.133 --username test -- -password 123456 --encrypt --start Using interface ppp0 Connect: ppp0 <--> /dev/pts/2 CHAP authentication succeeded MPPE 128-bit stateless compression enabled local IP address 192.168.9.100 remote IP address 192.168.140.128
出现CHAP authentication succeeded表示成功，而且会显示当前主机获取的IP地址，我这里是192.168.9.100.（该地址是在PPTP VPN服务器端配置的）
[[email protected] ~]# ip a |grep ppp 8: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1496 qdisc pfifo_fast state UNKNOWN qlen 3 link/ppp inet 192.168.9.100 peer 192.168.140.128/32 scope global ppp0 9: ppp1: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1496 qdisc pfifo_fast state UNKNOWN qlen 3 link/ppp inet 192.168.140.128 peer 192.168.9.100/32 scope global ppp1 [[email protected] ~]# ifconfig eth0 Link encap:Ethernet HWaddr 00:0C:29:B3:83:3F inet addr:192.168.49.133 Bcast:192.168.49.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:feb3:833f/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1657 errors:0 dropped:0 overruns:0 frame:0 TX packets:1240 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:223662 (218.4 KiB) TX bytes:153261 (149.6 KiB) eth1 Link encap:Ethernet HWaddr 00:0C:29:B3:83:49 inet addr:192.168.140.128 Bcast:192.168.140.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:feb3:8349/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:15 errors:0 dropped:0 overruns:0 frame:0 TX packets:445 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3158 (3.0 KiB) TX bytes:21306 (20.8 KiB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:377 errors:0 dropped:0 overruns:0 frame:0 TX packets:377 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:35490 (34.6 KiB) TX bytes:35490 (34.6 KiB) ppp0 Link encap:Point-to-Point Protocol inet addr:192.168.9.100 P-t-P:192.168.140.128 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1496 Metric:1 RX packets:6 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:3 RX bytes:60 (60.0 b) TX bytes:66 (66.0 b) ppp1 Link encap:Point-to-Point Protocol inet addr:192.168.140.128 P-t-P:192.168.9.100 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1496 Metric:1 RX packets:6 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:3 RX bytes:66 (66.0 b) TX bytes:60 (60.0 b)
这里因为我是在PPTP VPN Server上安装的pptp client，所以服务器端和客户端在一起，创建了两个ppp网卡。
[[email protected] ~]# ps -ef|grep ppp root 1389 1 0 23:23 pts/0 00:00:00 pptp 192.168.49.133 --nolaunchpppd root 1397 1 0 23:23 pts/0 00:00:00 pptp 192.168.49.133 --nolaunchpppd root 1399 1398 0 23:23 ? 00:00:00 /usr/sbin/pppd local file /etc/ppp/options.pptpd 115200 192.168.140.128:192.168.9.100 ipparam 192.168.49.133 plugin /usr/lib64/pptpd/pptpd-logwtmp.so pptpd-original-ip 192.168.49.133 remotenumber 192.168.49.133 root 1405 1 0 23:23 ? 00:00:00 pppd call vpn updetach root 1990 1118 0 23:29 pts/0 00:00:00 grep ppp
如果想要关闭ppp连接，只需要杀掉对应的进程即可，比如我这里是进程1399.
[[email protected] ~]# kill 1399 [[email protected] ~]# ifconfig eth0 Link encap:Ethernet HWaddr 00:0C:29:B3:83:3F inet addr:192.168.49.133 Bcast:192.168.49.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:feb3:833f/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:2107 errors:0 dropped:0 overruns:0 frame:0 TX packets:1596 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:264616 (258.4 KiB) TX bytes:196914 (192.2 KiB) eth1 Link encap:Ethernet HWaddr 00:0C:29:B3:83:49 inet addr:192.168.140.128 Bcast:192.168.140.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:feb3:8349/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:16 errors:0 dropped:0 overruns:0 frame:0 TX packets:466 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3500 (3.4 KiB) TX bytes:22704 (22.1 KiB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:408 errors:0 dropped:0 overruns:0 frame:0 TX packets:408 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:37460 (36.5 KiB) TX bytes:37460 (36.5 KiB)
当然，如果要重启启用ppp网络，只需执行以下命令即可。
pppd call [vpn连接名称]，如pppd call vpn.
[[email protected] ~]# pppd call vpn [[email protected] ~]# ip a |grep ppp 10: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1496 qdisc pfifo_fast state UNKNOWN qlen 3 link/ppp inet 192.168.9.100 peer 192.168.140.128/32 scope global ppp0 11: ppp1: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1496 qdisc pfifo_fast state UNKNOWN qlen 3 link/ppp inet 192.168.140.128 peer 192.168.9.100/32 scope global ppp1 [[email protected] ~]# ifconfig eth0 Link encap:Ethernet HWaddr 00:0C:29:B3:83:3F inet addr:192.168.49.133 Bcast:192.168.49.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:feb3:833f/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:2161 errors:0 dropped:0 overruns:0 frame:0 TX packets:1638 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:269604 (263.2 KiB) TX bytes:203202 (198.4 KiB) eth1 Link encap:Ethernet HWaddr 00:0C:29:B3:83:49 inet addr:192.168.140.128 Bcast:192.168.140.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:feb3:8349/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:16 errors:0 dropped:0 overruns:0 frame:0 TX packets:466 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3500 (3.4 KiB) TX bytes:22704 (22.1 KiB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:441 errors:0 dropped:0 overruns:0 frame:0 TX packets:441 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:39689 (38.7 KiB) TX bytes:39689 (38.7 KiB) ppp0 Link encap:Point-to-Point Protocol inet addr:192.168.9.100 P-t-P:192.168.140.128 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1496 Metric:1 RX packets:6 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:3 RX bytes:60 (60.0 b) TX bytes:66 (66.0 b) ppp1 Link encap:Point-to-Point Protocol inet addr:192.168.140.128 P-t-P:192.168.9.100 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1496 Metric:1 RX packets:6 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:3 RX bytes:66 (66.0 b) TX bytes:60 (60.0 b)
可以通过/var/log/message中的内容查看相关日志，如：
[[email protected] ~]# tail -f /var/log/messages Sep 6 04:01:08 localhost pppd[2907]: pppd 2.4.5 started by root, uid 0 Sep 6 04:01:08 localhost pppd[2907]: Using interface ppp0 Sep 6 04:01:08 localhost pppd[2907]: Connect: ppp0 <--> /dev/pts/2 Sep 6 04:01:08 localhost pptp[2908]: anon log[main:pptp.c:314]: The synchronous pptp option is NOT activated Sep 6 04:01:08 localhost pptp[2916]: anon log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 1 ‘Start-Control-Connection-Request‘ Sep 6 04:01:08 localhost pptpd[2917]: CTRL: Client 192.168.49.133 control connection started Sep 6 04:01:08 localhost pptp[2916]: anon log[ctrlp_disp:pptp_ctrl.c:739]: Received Start Control Connection Reply Sep 6 04:01:08 localhost pptp[2916]: anon log[ctrlp_disp:pptp_ctrl.c:773]: Client connection established. Sep 6 04:01:09 localhost pptp[2916]: anon log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 7 ‘Outgoing-Call-Request‘ Sep 6 04:01:09 localhost pptpd[2917]: CTRL: Starting call (launching pppd, opening GRE) Sep 6 04:01:09 localhost pptp[2916]: anon log[ctrlp_disp:pptp_ctrl.c:858]: Received Outgoing Call Reply. Sep 6 04:01:09 localhost pptp[2916]: anon log[ctrlp_disp:pptp_ctrl.c:897]: Outgoing call established (call ID 0, peer‘s call ID 128). Sep 6 04:01:09 localhost pppd[2918]: Plugin /usr/lib64/pptpd/pptpd-logwtmp.so loaded. Sep 6 04:01:09 localhost pppd[2918]: pppd 2.4.5 started by root, uid 0 Sep 6 04:01:09 localhost pppd[2918]: Using interface ppp1 Sep 6 04:01:09 localhost pppd[2918]: Connect: ppp1 <--> /dev/pts/3 Sep 6 04:01:09 localhost pppd[2918]: peer from calling number 192.168.49.133 authorized Sep 6 04:01:09 localhost pppd[2907]: CHAP authentication succeeded Sep 6 04:01:09 localhost pppd[2918]: MPPE 128-bit stateless compression enabled Sep 6 04:01:09 localhost pppd[2907]: MPPE 128-bit stateless compression enabled Sep 6 04:01:09 localhost pppd[2918]: Cannot determine ethernet address for proxy ARP Sep 6 04:01:09 localhost pppd[2918]: local IP address 192.168.140.128 Sep 6 04:01:09 localhost pppd[2918]: remote IP address 192.168.9.100 Sep 6 04:01:09 localhost pppd[2907]: local IP address 192.168.9.100 Sep 6 04:01:09 localhost pppd[2907]: remote IP address 192.168.140.128 Sep 6 04:01:11 localhost ntpd[1066]: Listen normally on 13 ppp0 192.168.9.100 UDP 123 Sep 6 04:01:11 localhost ntpd[1066]: peers refreshed
二、Windows客户端
相对于Linux客户端，Windows客户端也是比较容易设置的，毕竟PPTP协议的提出也有微软的参与，所以这方面的支持是少不了的，下面在windows7上设置客户端连接PPTP VPN.
在网络和共享中心，选择“设置新的连接或网络”
选择“连接到工作区”
选择“使用我的Ineternet连接（VPN）”
输入Internet地址，这个地址是VPN Server的地址，一般是外网IP地址，因为客户端要能ping到这个地址，当然也可以通过端口映射的方式映射内网IP到公网，结果是一样的。
输入PPTP VPN连接的用户名密码
等待连接建立
注册客户端
连接成功
查看连接信息，已经获取到IP地址，这里依然是服务器上设置的192.168.9.0/24段，至此，配置完成。
补充一点，如果自己要写脚本自动化ppp网络连接的开启或关闭，当然可以，不过ppp的工具包已经提供了相关的一些脚本，具体在/usr/share/doc/ppp-2.4.5/scripts/路径下。
[[email protected] scripts]# ll total 96 -rw-r--r-- 1 root root 5582 Nov 16 2009 autopppd -rw-r--r-- 1 root root 2301 Nov 16 2009 callback -rw-r--r-- 1 root root 2795 Nov 16 2009 chat-callback drwxr-xr-x 2 root root 4096 Sep 5 03:54 chatchat -rw-r--r-- 1 root root 603 Mar 16 2015 ip-down.local.add -rw-r--r-- 1 root root 818 Mar 16 2015 ip-up.local.add -rw-r--r-- 1 root root 86 Nov 16 2009 options-rsh-loc -rw-r--r-- 1 root root 92 Nov 16 2009 options-rsh-rem -rw-r--r-- 1 root root 86 Nov 16 2009 options-ssh-loc -rw-r--r-- 1 root root 92 Nov 16 2009 options-ssh-rem -rw-r--r-- 1 root root 146 Nov 16 2009 plog -rw-r--r-- 1 root root 2772 Nov 16 2009 poff -rw-r--r-- 1 root root 970 Nov 16 2009 pon -rw-r--r-- 1 root root 3604 Nov 16 2009 pon.1 -rw-r--r-- 1 root root 967 Nov 16 2009 ppp-off -rw-r--r-- 1 root root 1641 Nov 16 2009 ppp-on -rw-r--r-- 1 root root 397 Nov 16 2009 ppp-on-dialer -rw-r--r-- 1 root root 2018 Mar 16 2015 ppp-on-rsh -rw-r--r-- 1 root root 2307 Mar 16 2015 ppp-on-ssh -rw-r--r-- 1 root root 6190 Nov 16 2009 README -rw-r--r-- 1 root root 2237 Nov 16 2009 redialer -rw-r--r-- 1 root root 2374 Mar 16 2015 secure-card
里面有一些初始即可用，有一些需要加一些个性化设置，不过都是些不错的脚本，值得借鉴。