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NAT and Routed Network with Two ISP's on one router

I'm sure this has been done covered many times, but I am not finding it.


I have two ISP connections.

With ISP-A I have a /30 between us and is routed to me via the /30 for thsi example we will say the /30 is on isp end and on my end


With ISP-B I have a subnet. and the ISP gateway is on that subnet at


On the inside of my network I have devices using both 200.100.100.x addresses and devices on 192.168.100.x that need to use NAT.

I would like all of the devices on 200.100.100.x addresses to continue using ISP-A as their gateway.

Everything on 192.168.100.x should use NAT and go out ISP-B


I have tried

ip nat inside source route-map ISP-A interface GigabitEthernet0/1 overload

route-map ISP-A permit 10
 match ip address 101
 match interface GigabitEthernet0/1
 set ip next-hop
route-map ISP-A permit 10
 match ip address 111
 match interface Multilink1
 set ip next-hop

The problem comes when I have default routes to ISP-A in the router than none of the ISP-B traffic works, and vice versa.

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