yum install -y ppp pptp pptp-setup

pptpsetup --create VPN名字 --server 服务器IP --username 用户名 --password 密码 --encrypt --start 
[root@centos6-8-1 ~]# pptpsetup --create vpn --server 192.168.127.128 --username user --password passw
d --encrypt --start
Using interface ppp0
Connect: ppp0 <--> /dev/pts/2
CHAP authentication succeeded
MPPE 128-bit stateless compression enabled
local IP address 192.168.0.235
remote IP address 192.168.0.1

[root@centos6-8-1 ~]# ip addr

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host 
valid_lft forever preferred_lft forever

link/ether 00:0c:29:27:eb:e7 brd ff:ff:ff:ff:ff:ff
inet 192.168.127.129/24 brd 192.168.127.255 scope global eth0
inet6 fe80::20c:29ff:fe27:ebe7/64 scope link 
valid_lft forever preferred_lft forever
4: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1496 qdisc pfifo_fast state UNKNOWN qlen 3
link/ppp 
inet 192.168.0.235 peer 192.168.0.1/32 scope global ppp0

route add default dev ppp0

pkill pptp