We can use a cisco 2800 series router as a VPN server in a network, it can be used in a medium business, so there is a sample configuration for cisco 2811 as a PPTP VPN server:
Building configuration...
Current configuration : 1236 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
!
resource policy
!
ip subnet-zero
!
!
ip cef
!
--More-- !
vpdn enable
!
vpdn-group vpn
! Default PPTP VPDN group
accept-dialin
protocol pptp
virtual-template 1
!
!
!
voice-card 0
no dspfarm
!
!
!
!
!
!
!
!
!
!
--More-- !
!
!
!
!
username test password 0 test
!
!
!
!
!
!
!
interface Loopback0
ip address 200.200.200.200 255.255.255.255
!
interface FastEthernet0/0
ip address 210.10.10.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
--More-- shutdown
duplex auto
speed auto
!
interface Serial0/0/0
no ip address
shutdown
no fair-queue
clock rate 2000000
!
interface Serial0/0/1
no ip address
shutdown
clock rate 2000000
!
interface Virtual-Template1
ip unnumbered FastEthernet0/0
peer default ip address pool vpn
ppp encrypt mppe auto required
ppp authentication ms-chap ms-chap-v2
!
ip local pool vpn 100.0.0.1 100.0.0.10
ip classless
--More-- !
!
ip http server
no ip http secure-server
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
--More-- login
!
scheduler allocate 20000 1000
!
end
Router#
