PPTP VPN Server

A Cisco router can be configured as a PPTP VPN server. This is very handy, because a PPTP client is built into most operating systems, like Windows, Linux and Android.

For starters, you will need some users created. The VPN authentication mechanism can't use secret passwords, so you can only use type 7 or plaintext. It might work with external authentication like TACACS+ or RADIUS, but I haven't tried it.

username vpnuser password vpnpassword

Next, enable Virtual Private Dialup Networking (VPDN). When a user connects, they will be brought up on an interface created from the Virtual-Template interface.

vpdn enable
!
vpdn-group 1
 description PPTP VPN
 accept-dialin
  protocol pptp
  virtual-template 1

interface Virtual-Template1

description PPTP VPN
no ip dhcp client request router
! name of the LAN interface below
ip unnumbered FastEthernet0
no ip redirects
ip nat inside
ip virtual-reassembly
ip route-cache flow
no logging event link-status
peer default ip address pool PPTP-POOL
keepalive 30
ppp encrypt mppe 40
ppp authentication pap chap ms-chap

! ip local pool PPTP-POOL 192.168.10.230 192.168.10.234