Choose NAME of connection, VPNSERVER of your institution and your LOGIN
$ cat /etc/ppp/peers/NAME
pty "pptp VPNSERVER --nolaunchpppd"
name LOGIN
remotename PPP
require-mppe-128
file /etc/ppp/options.pptp
ipparam NAME
Choose LOGIN and PASSWORD
$ cat /etc/ppp/chap-secrets
# client server secret IP addresses
LOGIN PPP PASSWORD *
Now you simply run
pppd call NAME
route add -net ADDRESS_OF_NETWORK netmask 255.255.0.0 dev ppp0
