CentOS provides an PPTP solutions in the repository,
STEP 1. Install PPTP
sudo yum update sudo yum -y install pptp sudo modprobe nf_conntrack_pptp sudo modprobe ppp_mppe
STEP 2. Run sudo vi /etc/ppp/chap-secrets to edit the chap-secret file as shown below:
# Secrets for authentication using CHAP # client server secret IP addresses vpnusername PPTP vpnpassword *
Note that you should put space or tab between elements listed above.
STEP 3. Run vi /etc/ppp/peers/myvpn and enter the following information. You can create your own name whatever instead of myvpn.
pty "pptp usca.pointtoserver.com -nolaunchpppd" name your VPNusername remotename PPTP require-mppe-128 file /etc/ppp/options.pptp ipparam yourVPNName
https://support.purevpn.com/command-line-setup-in-linux-centos