Guide:
http://www.hh.se/download/18.70cf2e49129168da015800028616/module06

På router4:

Router(config)#ip local pool VPN 10.28.34.250 10.28.34.254
Router(config)#aaa new-model
Router(config)#aaa authorization network vpn-remote-access local
Router(config)#crypto isakmp enable
Router(config)#crypto isakmp policy 1
Router(config-isakmp)#authen pre-share
Router(config-isakmp)#encryption 3des
Router(config-isakmp)#group 2
Router(config-isakmp)#exit
Router(config)#crypto isakmp client configuration group vpn-remote-access

Router(config-isakmp-group)#key Cisco
Router(config-isakmp-group)#pool VPN

Router(config)#crypto ipsec transform-set VPNTRANSFORM esp-3des esp-sha-hmac

Router(config)#crypto dynamic-map DYNMAP 1
Router(config-crypto-map)#set transform-set VPNTRANSFORM
Router(config-crypto-map)#reverse-route

Router(config)#crypto map CLIENTMAP isakmp authorization list vpn-remote-access
Router(config)#crypto map CLIENTMAP client configuration address respond
Router(config)#crypto map CLIENTMAP 65535 ipsec-isakmp dynamic DYNMAP

Router(config)#int fa0/0
Router(config-if)#crypto map CLIENTMAP
*Jan  3 07:16:26.785: %CRYPTO-6-ISAKMP_ON_OFF: ISAKMP is ON
Router(config-if)#exit

Router(config)#crypto map CLIENTMAP client authentication list VPNUSERS