Introduce Default Routes by Protocol

03 Mar 2011 - Lab-Rat

BGP
neighbor {ip-address | peer-group-name} default-originate [route-map map-name]

RIP
Router(config-router)# default-information originate route-map condition

OSPF
Router(config-router)# default-information originate [always] [metric metric-value] [metric-type type-value] [route-map map-name]

EIGRP
Option 1
ip route 0.0.0.0 0.0.0.0 x.x.x.x
router eigrp 100
redistribute static
default-metric 10000 1 255 1 1500

Option 2
ip summary-address eigrp 100 0.0.0.0 0.0.0.0*

* Careful- This causes the creation of an EIGRP summary default route to the null 0 interface with an administrative distance of 5, which can override default routes from neighbors, and result in dropped traffic. In this scenario, limit the scope of the default route to a given interface using a distribute-list command, and filter all routes except 0.0.0.0.

Additional Reading:
RIP
http://www.cisco.com/en/US/docs/ios/12_0/np1/command/reference/1rrip.html

OSPF
http://www.cisco.com/en/US/docs/ios/iproute_ospf/configuration/guide/iro_cfg_ps6441_TSD_Products_Configuration_Guide_Chapter.html

EIGRP
http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080094cb7.shtml http://www.cisco.com/en/US/docs/ios/iproute_eigrp/configuration/guide/ire_cfg_eigrp_ps6441_TSD_Products_Configuration_Guide_Chapter.html#wp1060174

BGP
http://www.cisco.com/en/US/docs/ios/iproute_bgp/configuration/guide/irg_basic_net_ps6441_TSD_Products_Configuration_Guide_Chapter.html#wp1054164