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Statically NAT'd IPs don't come across site-to-site VPN

mikeb
Level 1
Level 1

Hello, I have a curious issue with a VPN that I hope somone can shed some light on.  I have a site-to-site VPN with one location having both overload and static NATs on the same interface as the VPN.  I have connectivity and verified that the VPN is working. 

The problem is when I try to access a host that has a static NAT from across the VPN, the traffic doesn't come across.  I am assuming that the return packets are being translated and never arriving.  Below are the relavant sections from both configs.  If someone could let me know what I'm missing that would help me out of a pinch!

Thanks

GR (172.17.0.0/16)

crypto map GRO-ROO 1 ipsec-isakmp

set peer X.X.X.X

set transform-set CDHSET

match address 115

ip nat inside source route-map nonat interface BVI99 overload

ip nat inside source static 172.17.10.96 X.X.X.X  (Public IP)

access-list 110 deny   ip 172.17.0.0 0.0.255.255 172.18.0.0 0.0.255.255

access-list 110 deny   ip host 172.17.10.96 any

access-list 110 deny   ip host 172.17.10.71 any

access-list 110 deny   ip host 172.17.10.60 any

access-list 110 deny   ip host 172.17.10.51 any

access-list 110 deny   ip host 172.17.10.76 any

access-list 110 deny   ip host 172.17.10.94 any

access-list 110 deny   ip host 172.17.10.77 any

access-list 110 deny   ip host 172.17.10.72 any

access-list 110 deny   ip host 172.17.10.53 any

access-list 110 deny   ip host 172.17.10.56 any

access-list 110 permit ip 172.17.0.0 0.0.255.255 any

access-list 115 permit ip 172.17.0.0 0.0.255.255 172.18.0.0 0.0.255.255

route-map nonat permit 10

match ip address 110

RO (172.18.0.0/16)

crypto map GRO-ROO 1 ipsec-isakmp

set peer Y.Y.Y.Y

set transform-set CDHSET

match address 115

ip nat inside source route-map nonat interface FastEthernet0/0 overload

access-list 110 deny   ip 172.18.0.0 0.0.255.255 172.17.0.0 0.0.255.255

access-list 110 permit ip 172.18.0.0 0.0.255.255 any

access-list 115 permit ip 172.18.0.0 0.0.255.255 172.17.0.0 0.0.255.255

route-map nonat permit 10

match ip address 110

1 Reply 1

Santhosha Shetty
Cisco Employee
Cisco Employee

Hi Mike,

As per crypto access-list 115 , I see the allowed source subnet is actual LAN(172.17.x.x). One thing to note is when you configure NAT for vpn traffic , one will have to use source subnet in the crypto access-list as NATed IP subnet because crypto access-list look up happens after the NAT.

 

HTH,

 

Santhosh