I installed vpn application as,

Then, i defined server ip and client ip range in /etc/pptpd.conf as,

Then, i define DNS server for pptp clients in /etc/ppp/pptpd-options as,

After that, i defined vpn users in /etc/ppp/chap-secrets as,

Then, i setup ip forwarding and define rules in iptables as,

 

That’s it. Cheers!!