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NAT Hairpin on a 1700 router


I've got a setup where a router has 2 connections to the public internet, 1 DSL (ethernet to a DSL modem) and 1 T1.

Clients want to use the upload of the T1 for certain services (since the DSL upload is 1/2 the speed).

Clients behind the router have static IPs for the T1 ISP, but the default route is currently going out DSL.

I'd like to figure out how I can make services be accessible by a staticly NATed DSL IP and their T1 IP at the same time.

With the current setup, only traffic from the DSL IP would work, because the default route sends all traffic back out the DSL.

It seems like I need some sort of NAT hairpinning to make sure traffic gets sent back out the same interface.

Is this possible on a 1700?

Here are relevant parts of the config:

interface Loopback0

ip address


interface Ethernet0

description DSL

ip address

ip nat outside

ip virtual-reassembly



interface FastEthernet0

description LAN

ip address yyy.yyy.yyy.161

ip nat inside

ip virtual-reassembly

speed auto


interface Serial0

description T1

ip unnumbered Loopback0

ip virtual-reassembly

encapsulation ppp

ip route 10

ip route Serial0 20

ip nat pool DSLPOOL netmask

ip nat inside source list 1 pool DSLPOOL

ip nat inside source static yyy.yyy.yyy.162 route-map dslstatic

route-map dslstatic permit 10

match interface Ethernet0

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