Juniper JUNOSE, Configuration Manual

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Policy specified by a route map with the default-information originate command
is applied at the same time as the policy for redistributed routes, before any
outbound policy for peers.
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Example
host1(config)# router bgp 100
host1(config-router)# default-information originate
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Use the no version to restore the default, preventing the redistribution of default
routes.
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See default-information originate.
Setting a Static Default Route
You might not want your routers to rely on dynamically learned default routes.
Instead, you might prefer to specify a static default route that your routers use to
forward traffic when they do not have a routing entry for a destination. Use the
ip
route command to configure a default route on a router. The static route can point
to a network number, an IP address, or a physical interface. You can add a distance
value to give preference to a specific static route when multiple entries exist for the
same route.
Suppose that in Figure 16 on page 58, router KC has been configured to advertise a
default route to router Chicago:
host1(config)# router bgp 62
host1(config-router)# network 172.17.24.0 mask 255.255.248.0
host1(config-router)# neighbor 10.8.3.1 remote-as 21
host1(config-router)# neighbor 10.8.3.1 default-originate
You prefer that router Chicago send traffic with unknown destinations to router
StLouis, so you configure a static default route on router Chicago:
host2(config)# router bgp 21
host2(config-router)# network 192.168.48.0 mask 255.255.240.0
host2(config-router)# neighbor 10.8.3.4 remote-as 62
host2(config-router)# neighbor 10.24.5.1 remote-as 37
host2(config-router)# exit
host2(config)# ip route 0.0.0.0 0.0.0.0 172.25.122.0
Router StLouis is configured to advertise network 172.25.122.0/23 to router Chicago:
host3(config)# router bgp 37
host3(config-router)# network 172.25.122.0 mask 255.255.254.0
host3(config-router)# neighbor 10.24.5.3 remote-as 21
Advertising Routes
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Chapter 1: Configuring BGP Routing