兩個私網可以同時上INTERNET和在私網這間通過IP SEC VPN通訊
 

剛用7400做了測試，讓兩個私網的IP可以上INTERNET和保證兩個私網的私有通訊。
LAN（192.168.2.0)--（G0/1）7400（G0/0）-----------（G0/0）7400--（G0/1）------LAN
7400的版本c7400-jk8o3s-mz.122-4.B7.bin
VPN-SERVER-R的配置如下：
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname VPN_SERVER_R
!
enable secret 5 $1$/xUJ$FPUpACBRvHlu3GuShRfAS1
enable password cisco
!
ip subnet-zero
!
!
!
ip audit notify log
ip audit po max-events 100
ip ssh time-out 120
ip ssh authentication-retries 3
!
crypto isakmp policy 10
authentication pre-share
crypto isakmp key abc2001 address 10.72.200.102
!
!
crypto ipsec transform-set abc-des esp-des esp-sha-hmac
crypto mib ipsec flowmib history tunnel size 200
!
crypto map abc 20 ipsec-isakmp
set peer 10.72.200.102
set transform-set abc-des
match address 105
!
!
!
!
interface GigabitEthernet0/0
ip address 10.72.200.124 255.255.255.240
ip nat outside
duplex auto
speed auto
media-type rj45
crypto map abc
!
interface GigabitEthernet0/1
ip address 192.168.2.1 255.255.255.0
ip nat inside
duplex auto
speed auto
media-type rj45
!
ip nat inside source route-map abc interface GigabitEthernet0/0 overload
ip classless
ip route 0.0.0.0 0.0.0.0 10.72.200.113
no ip http server
ip pim bidir-enable
!
access-list 105 permit ip 192.168.2.0 0.0.0.255 192.168.1.0 0.0.0.255
access-list 150 deny ip 192.168.2.0 0.0.0.255 192.168.1.0 0.0.0.255
access-list 150 permit ip 192.168.2.0 0.0.0.255 any
dialer-list 1 protocol ip permit
dialer-list 1 protocol ipx permit
!
route-map abc permit 10
match ip address 150
!
!
!
call rsvp-sync
!
!
mgcp profile default
!
dial-peer cor custom
!
!
!
!
gatekeeper
shutdown
!
!
line con 0
line aux 0
line vty 0 4
password cisco
login
!
!
end
VPN-SEVER的配置如下：
!
version 12.2
no parser cache
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname vpn_server
!
logging rate-limit console 10 except errors
enable secret 5 $1$oOeg$gKas7oy5fsdCRLob2YQ/m1
!
ip subnet-zero
!
!
!
ip audit notify log
ip audit po max-events 100
ip ssh time-out 120
ip ssh authentication-retries 3
no ip dhcp-client network-discovery
!
crypto isakmp policy 10
authentication pre-share
crypto isakmp key abc2001 address 10.72.200.124
!
!
crypto ipsec transform-set abc-des esp-des esp-sha-hmac
!
crypto map abc 20 ipsec-isakmp
set peer 10.72.200.124
set transform-set abc-des
match address 105
!
call rsvp-sync
!
!
!
!
interface GigabitEthernet0/0
ip address 10.72.200.102 255.255.255.240
ip nat outside
duplex auto
speed auto
media-type rj45
crypto map abc
!
interface GigabitEthernet0/1
ip address 192.168.1.1 255.255.255.0
ip nat inside
duplex auto
speed auto
media-type rj45
!
ip nat inside source route-map abc interface GigabitEthernet0/0 overload
ip classless
ip route 0.0.0.0 0.0.0.0 10.72.200.97
no ip http server
!
access-list 105 permit ip 192.168.1.0 0.0.0.255 192.168.2.0 0.0.0.255
access-list 150 deny ip 192.168.1.0 0.0.0.255 192.168.2.0 0.0.0.255
access-list 150 permit ip 192.168.1.0 0.0.0.255 any
!
!
route-map abc permit 10
match ip address 150
!
!
!
!
!
gatekeeper
shutdown
!
!
line con 0
line aux 0
line vty 0 4
password cisco
login
line vty 5 15
login
!
!
end

這種方式比較適合大規模多分支機構的集團服務機構的通訊。
VPN-SERVER的配置:

注意:我把一端的ABC改為了N0_NAT一樣可以互通

!
version 12.2
no parser cache
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname vpn_server
!
logging rate-limit console 10 except errors
enable secret 5 $1$oOeg$gKas7oy5fsdCRLob2YQ/m1
!
ip subnet-zero
!
!
!
ip audit notify log
ip audit po max-events 100
ip ssh time-out 120
ip ssh authentication-retries 3
no ip dhcp-client network-discovery
!
crypto isakmp policy 10
authentication pre-share
crypto isakmp key abc2001 address 10.72.200.124
!
!
crypto ipsec transform-set abc-des esp-des esp-sha-hmac
mode transport
!
crypto map no_nat 200 ipsec-isakmp
set peer 10.72.200.124
set transform-set abc-des
match address 105
!
call rsvp-sync
!
!
!
!
!
!
!
!
!
interface GigabitEthernet0/0
ip address 10.72.200.102 255.255.255.240
ip nat outside
duplex auto
speed auto
media-type rj45
crypto map no_nat
!
interface GigabitEthernet0/1
ip address 192.168.1.1 255.255.255.0
ip nat inside
duplex auto
speed auto
media-type rj45
!
ip nat inside source route-map no_nat interface GigabitEthernet0/0 overload
ip classless
ip route 0.0.0.0 0.0.0.0 10.72.200.97
no ip http server
!
access-list 105 permit ip 192.168.1.0 0.0.0.255 192.168.2.0 0.0.0.255
access-list 150 deny ip 192.168.1.0 0.0.0.255 192.168.2.0 0.0.0.255
access-list 150 permit ip 192.168.1.0 0.0.0.255 any
!
!
route-map no_nat permit 10
match ip address 150
!
!
!
!
!
gatekeeper
shutdown
!
!
line con 0
line aux 0
line vty 0 4
password cisco
login
line vty 5 15
login
!
!
end