I have the following problem, and can't seem to find a solution.
I have 2 Cisco routers, A and B with a VPN connection. Both routers have a serial
interface pointing to external and an ethernet interface (Lets call them A and B)
pointing to the inside.
Traffic between subnet A and B is NOT NATed and the VPN works fine.
Now, router B has a second ethernet interface (C), to subnet C.
I added this subnet to the IPSEC ACLS on both routers as I want to allow subnet A to
access subnet C through the VPN.
The tunnel is up and running with no NAT being done.
However, on router B, access from subnet B to C is NATed:
ip nat inside
ip nat outside
ip nat inside source route-map NAT interface C overload
route-map NAT permit 10
match ip address 123
access-list 123 permit ip SUBNET_B SUBNET_C
So far so good. Now the problem:
How can I NAT traffic from subnet A to subnet C?
I tried adding
access-list 123 permit ip SUBNET_A SUBNET_C
but this doesn't help as traffic coming out of the VPN seems not to be affected by the
NAT rule, probably because it is not considered coming from an interface with "ip nat
Is there a way of doing this without using tunnel interfaces?
Thanks in advance,
If I understood it correctly, you want the traffic from Subnet A to reach the router B, get decrypted, NATted to interface B and thten routed to interface C.
Please correct me if I am wrong.
You might want to use PBR (Policy Based Routing) for this.
Create an ACL to identify the traffic:
access-list 101 permit ip Subnet A Subnet C
Create a loopback :
int loopback 1
ip address 126.96.36.199 255.255.255.252
ip nat inside
Create a route map to route the traffic after its decrypted.
route-map pol_nat permit 10
match ip address 101
set ip next-hop 188.8.131.52
Apply the route map to your WAN interface:
int serial 0
ip policy route-map pol_nat
This way the traffic will first be decrypted and then will be routed to loopback, which has a "ip nat inside" applied, and then it will be routed to subnet C after being natted using your NAT rule.
*Please rate if this helps.