Сведу все воедино и в решенные бы отправить
aaa new-model
!
aaa authentication ppp default local-case
aaa authorization exec default local
aaa authorization network default local
!
aaa attribute list user-ivanov
attribute type addr 10.10.10.51 service ppp protocol ip mandatory
!
username ivanov privilege 0 password 0 IvanovPassword
username ivanov aaa attribute list user-ivanov
vpdn-group VPDN-PPTP
! Default PPTP VPDN group
accept-dialin
protocol pptp
virtual-template 1
pptp tunnel echo 10
ip pmtu
ip mtu adjust
interface Virtual-Template1
ip unnumbered Loopback0
ip virtual-reassembly
autodetect encapsulation ppp
ppp encrypt mppe 40
ppp authentication ms-chap-v2