Encontrou a solução para usar a conexão PPTP com a VM no link
O que eu estava perdendo quando tentei me conectar na VM:
2.3 If /sbin/route shows that there is default route for current network connection, we have to add another default route for ppp0 to be able to use the vpn. This is because pppd's defaultroute option does not override existing default (by design). The ip-up.local is a script that is executed after the connection has been established:
create file /etc/ppp/ip-up.local and add the following:
/sbin/route add default ppp0
make ip-up.local executable:
sudo chmod 755 /etc/ppp/ip-up.local