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Configure On-Demand Routing (ODR) on Cisco routers


ODR is used to allow hub routers to accept prefix information, distributed via Cisco Discovery Protocol (CDP) , from spoke routers.


On the hub router, enter this command
router odr

Also, routes can be controlled with a distribute-list:
distribute-list 10 in
distribute-list 20 out
assuming the referenced ACLs exist, otheriwse no routes are accepted or sent.

Since the prefix updates are carried on CDP, ODR updates can be controlled, in true sledgehammer fashion, by disabling CDP on an interface:interface serial 0/0
no cdp enable

For ODR to work properly, all dynamic routing protocols need to be disabled on the spoke routers.
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