Consolidating routers, PBR & routing sub-intf's thru a Pix

[Steve M.]

I'm consolidating several older 25xx routers into a new 3725. I have four serial interfaces & 2 fastethernet (fe) interfaces in the 3725. I'm needing to route each serial interface through a separate Pix interface (I have 6 Pix fastethernet interfaces).

Since I have fewer physical fe intf's than serial intf's, I've figured that sub-interfaces was the way to go. I can use 802.11q on the switches the Pix & 3725 connect to, 3725 sub-interfaces, etc.

My dilemna is ensuring that traffic originating on s0/0 will be sent only through f0/0, not look up the routing table (therefore bypassing the Pix) and be sent out f0/1 or f0/2. The goal is to have only one interface provide actual routing (using the internal table) -- the serial interface that connects to the Internet. The rest of the connections are private and shouldn't go directly to any other interface, but rather through the Pix and then either to another router or through another Pix interface (the Pix's interface would connect to a different serial interface on the 3725).

Would policy-based routing (PBR) fit the criteria for the above or is there a different way to "dumb" the router down to simply bridge between certain specified interfaces?

Thanks in advance.

[geoff.belknap]

Ideally, if this is your internet router you would ensure that the default route on the 3725 points to the PIX (ip route 0.0.0.0 0.0.0.0 ).

Typically, Policy Based Routing is done with a route map and access-list that match a source and a destination. It's going to be more than a little difficult to create a reasonable acess list with a source of "The internet".

But, depending on your scenario, if you absolutely need Policy-Based Routing, here are a few examples for you:

When to use Policy-Based Routing:

http://www.cisco.com/en/US/customer/products/sw/iosswrel/ps1828/products_configuration_guide_chapter09186a00800ca58f.html#xtocid293866

Configuring Policy-Based Routing:

http://www.cisco.com/en/US/customer/products/sw/iosswrel/ps1828/products_configuration_guide_chapter09186a00800ca590.html

Hope this helps,

-Geoff