! Config for pix pptp vpn 

sysopt connection permit-pptp
ip local pool WIN-VPN 172.16.0.1-172.16.0.254
access-list NONAT extended permit ip (INSIDENETWORK) (INSIDEMASK) 172.16.0.0 255.255.255.0

nat (inside) 0 access-list NONAT
vpdn group 1 accept dialin pptp
vpdn group 1 ppp authentication pap
vpdn group 1 ppp authentication chap
vpdn group 1 ppp authentication mschap
vpdn group 1 ppp encryption mppe 40 required
vpdn group 1 client configuration address local WIN-VPN
vpdn group 1 client configuration dns 192.168.1.10
vpdn group 1 pptp echo 60
vpdn group 1 client authentication local
vpdn username sales password s@lesm@n
vpdn enable outside