1

I'm trying to configure VPN between 2 routers:

  1. R1: public IP is 200.0.0.6/30 on S0/0/1, private IP are 10.0.0.0/8 and 20.0.0.0/8
  2. R3: public IP is 210.10.0.6/30 on S0/0/0, private IP is 192.168.3.0/24

Configuration:

  1. On R1:
crypto isakmp policy 10
 encr aes
 authentication pre-share
 group 2
!
crypto isakmp key SECRET_KEY address 210.10.0.6
!
!
!
crypto ipsec transform-set VPN-TRANSFORM esp-aes esp-sha-hmac
!
crypto map VPN-MAP 10 ipsec-isakmp 
 set peer 210.10.0.6
 set transform-set VPN-TRANSFORM 
 match address VPN-TRAFFIC
!
!
!
!
!
!
spanning-tree mode pvst
!
!
!
!
!
!
interface FastEthernet0/0
 ip address 10.0.0.1 255.0.0.0
 duplex auto
 speed auto
!
interface FastEthernet0/1
 no ip address
 duplex auto
 speed auto
 shutdown
!
interface Serial0/0/0
 ip address 20.0.0.1 255.0.0.0
 clock rate 2000000
!
interface Serial0/0/1
 ip address 200.0.0.6 255.255.255.252
 crypto map VPN-MAP
!
interface Vlan1
 no ip address
 shutdown
!
router eigrp 10
 network 10.0.0.0
 network 20.0.0.0
 auto-summary
!
ip classless
ip route 0.0.0.0 0.0.0.0 Serial0/0/1 
!
ip flow-export version 9
!
!
ip access-list extended VPN-TRAFFIC
 permit ip 10.0.0.0 0.255.255.255 192.168.3.0 0.0.0.255
 permit ip 20.0.0.0 0.255.255.255 192.168.3.0 0.0.0.255
 permit ip 192.168.3.0 0.0.0.255 10.0.0.0 0.255.255.255
 permit ip 192.168.3.0 0.0.0.255 20.0.0.0 0.255.255.255
  1. On R3:
crypto isakmp policy 10
 encr aes
 authentication pre-share
 group 2
!
crypto isakmp key SECRET_KEY address 200.0.0.6
!
!
!
crypto ipsec transform-set VPN-TRANSFORM esp-aes esp-sha-hmac
!
crypto map VPN-MAP 10 ipsec-isakmp 
 set peer 200.0.0.6
 set transform-set VPN-TRANSFORM 
 match address VPN-TRAFFIC
!
!
!
!
!
!
spanning-tree mode pvst
!
!
!
!
!
!
interface FastEthernet0/0
 ip address 192.168.3.1 255.255.255.0
 duplex auto
 speed auto
!
interface FastEthernet0/1
 no ip address
 duplex auto
 speed auto
 shutdown
!
interface Serial0/0/0
 ip address 210.10.0.6 255.255.255.252
 crypto map VPN-MAP
!
interface Serial0/0/1
 no ip address
 clock rate 2000000
 shutdown
!
interface Vlan1
 no ip address
 shutdown
!
ip classless
ip route 0.0.0.0 0.0.0.0 Serial0/0/0 
!
ip flow-export version 9
!
!
ip access-list extended VPN-TRAFFIC
 permit ip 192.168.3.0 0.0.0.255 10.0.0.0 0.255.255.255
 permit ip 192.168.3.0 0.0.0.255 20.0.0.0 0.255.255.255
 permit ip 10.0.0.0 0.255.255.255 192.168.3.0 0.0.0.255
 permit ip 20.0.0.0 0.255.255.255 192.168.3.0 0.0.0.255

But there was nothing when I entered sh crypto isakmp sa and sh crypto ipsec sa. I could not ping 2 routers also. Plz help me out. Thankyou!

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4
  • 1
    The two routers need a shared network on the link between them.
    – Ron Maupin ♦
    Apr 9 at 8:11
  • These 2 routers don't have physical connection. I tried to connect them by using gre tunnel interface but it didn't work. Do you have any other idea?
    – Gekko
    Apr 9 at 15:31
  • You don't have NAT setup and are attempting to use non-routable (RFC1918) IP addresses. Aside from that, you need to debug the crypto process and initiate some qualified traffic and see if the VPN tunnel attempts phase 1 or phase 2, and what goes wrong.
    – FrameHowitzer
    Apr 9 at 22:56
  • So you mean (1) I don't have to use GRE tunnel, (2) instead use NAT and (3) debug crypto [isakmp, ipsec], right?
    – Gekko
    Apr 10 at 0:31

1 Answer 1

Reset to default
0

I solved it!

Here is my network model:

network model

There are some changes in configurations. About routing, I used OSPF for public routing (single area). I still keep EIGRP for private routing I did before. Then redistribute them. About access-lists, I deleted last 2 unnecessary lines in each one on each router. And some changes in crypto policy, key, transform-set, map as below:

On R1:

crypto isakmp policy 10
 encr 3des
 hash md5
 authentication pre-share
 group 5
 lifetime 50000
!
crypto isakmp key cisco123 address 210.10.0.6
!
!
!
crypto ipsec transform-set tset esp-3des esp-md5-hmac
!
crypto map smap 1 ipsec-isakmp 
 set peer 210.10.0.6
 set transform-set tset 
 match address vpn
!
!
!
!
!
!
spanning-tree mode pvst
!
!
!
!
!
!
interface FastEthernet0/0
 ip address 10.0.0.1 255.0.0.0
 duplex auto
 speed auto
!
interface FastEthernet0/1
 no ip address
 duplex auto
 speed auto
 shutdown
!
interface Serial0/0/0
 ip address 20.0.0.1 255.0.0.0
 clock rate 2000000
!
interface Serial0/0/1
 ip address 200.0.0.6 255.255.255.252
 crypto map smap
!
interface Vlan1
 no ip address
 shutdown
!
router eigrp 10
 redistribute ospf 1 metric 1 1 1 1 1 
 network 10.0.0.0
 network 20.0.0.0
 network 0.0.0.0
 auto-summary
!
router ospf 1
 log-adjacency-changes
 redistribute eigrp 10 
 network 200.0.0.4 0.0.0.3 area 0
!
ip classless
ip route 0.0.0.0 0.0.0.0 Serial0/0/1 
!
ip flow-export version 9
!
!
ip access-list extended vpn
 permit ip 10.0.0.0 0.255.255.255 192.168.3.0 0.0.0.255
 permit ip 20.0.0.0 0.255.255.255 192.168.3.0 0.0.0.255

On R3:

crypto isakmp policy 10
 encr 3des
 hash md5
 authentication pre-share
 group 5
 lifetime 50000
!
crypto isakmp key cisco123 address 200.0.0.6
!
!
!
crypto ipsec transform-set tset esp-3des esp-md5-hmac
!
crypto map smap 1 ipsec-isakmp 
 set peer 200.0.0.6
 set transform-set tset 
 match address vpn
!
!
!
!
!
!
spanning-tree mode pvst
!
!
!
!
!
!
interface FastEthernet0/0
 ip address 192.168.3.1 255.255.255.0
 duplex auto
 speed auto
!
interface FastEthernet0/1
 no ip address
 duplex auto
 speed auto
 shutdown
!
interface Serial0/0/0
 ip address 210.10.0.6 255.255.255.252
 crypto map smap
!
interface Serial0/0/1
 no ip address
 clock rate 2000000
 shutdown
!
interface Vlan1
 no ip address
 shutdown
!
router eigrp 10
 redistribute ospf 1 metric 1 1 1 1 1 
 network 192.168.3.0
 auto-summary
!
router ospf 1
 log-adjacency-changes
 redistribute eigrp 10 
 network 210.10.0.4 0.0.0.3 area 0
!
ip classless
!
ip flow-export version 9
!
!
ip access-list extended vpn
 permit ip 192.168.3.0 0.0.0.255 10.0.0.0 0.255.255.255
 permit ip 192.168.3.0 0.0.0.255 20.0.0.0 0.255.255.255

I realize 2 routers R1 and R3 need to be routed.

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