Our facility has 2 Internet connections and because of our current route config we can only utilize 1 of them. One connection is a 3660 router with 3 T1 serial interfaces configured in a Multilink. This Multilink interface connects to a MPLS network and then the Internet. The 3660 connects to a core switch.

The second internet connection is a single T1 serial connection attached to a smaller router. This router also connects to the core switch.

Our external DNS entries point to the single T1 connection so our systems can be access from the outside. We have default static route sending all traffic out this single T1. We tried removing the static route to send all traffic out the MPLS links. This worked except for the 'responses' our servers sent back to external requests also went out the MPLS links. Basically, and external request was coming in the single T1 then the response was sent out the MPLS link.

Would some form of ACL config fix this problem? We only have approximately 15 IP address's with external DNS entries.