Hi,
We have an edge router with two ISP links terminated on it. Serial 1 - ISP1 and Seril 2 - ISP2, Ethernet 0 is connected to internal infrastructure.
Following is the configuration:
access-list standard office_1
pemit office_1 LAN_subnet
route_map ABCD permit 10
match ip address office_1 ( matches packets with source IP address form ofice_1 subnet )
set ip next_hop ISP2_IP_address ( Packets with source IP from office_1 subnet will be forwarded to serial 2 link towards ISP2 )
interface eth0
ip policy route-map ABCD ( apply policy map on inside interface )
ip nat inside
ip nat inside source route-map ABCD Outside_interface overload ( ISP1-serial 1 )
int s1
ip nat outside
int s2
ip route 0.0.0.0 0.0.0.0 ISP1_IP ( serial 1 )
Under normal condition it is expected that packets from office_1 will be policy routed to ISP2 link and all other packets will be routed to ISP1 link.
In case ISP2 link down, will the "NAT" statement kick in only if the Next_hop_address ISP2 side is not reachable.
This will cause the packets with source IP from office_1 subnet will be NATed with the source IP of the ISP1-serial_1 IP and will be forwared to ISP1 link. Indirectly this NAT will compe into play only in case ISP2 link is down. This will kind of provie a "conditional" NAT.
Are these assumptions true or anything else can take place?
Please share the experience.
Thanks in advance!
Subodh
