I have a 831 router with the c831-k9o3y6-mz.123-2.XC2.bin software image. I have set the router to accept incoming PPTP tunnels which works fine with Windows XP workstations. When I try to connect via a Vista or Windows 7 machine I get to "Registering your computer on the network..." and it fails with "Error 742: The remote computer does not support the required data encryption type."
I have the following commands...
! Default PPTP VPDN group
ip unnumbered Ethernet1
peer default ip address pool VPNUSERS
ppp encrypt mppe auto required
ppp authentication ms-chap ms-chap-v2
Any help would be greatly appreciated.