sudo apt-get install pptpd
sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE && iptables-save
sudo iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS  --clamp-mss-to-pmtu

sudo nano /etc/ppp/chap-secrets
>>> box1 pptpd passwordhere *
>>> box2 pptpd passwordhere *

sudo nano /etc/ppp/pptpd-options
>>> ms-dns 8.8.8.8
>>> ms-dns 8.8.4.4

sudo nano /etc/pptpd.conf
>>> localip 10.0.0.1
>>> remoteip 10.0.0.100-200

sudo nano /etc/sysctl.conf
>>> net.ipv4.ip_forward = 1

sudo sysctl -p
sudo service pptpd restart