Default-originate Vs bgp cluster-id

Unanswered Question

Hi Edy!

I Didn't Find the Default-Route

R6# sh ip bgp neighbors advertised-routes

BGP table version is 5, local router ID is

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

r RIB-failure, S Stale

Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path

*>i150.1.1.0/24 0 100 0 i

*>i159.1.1.0/24 0 100 0 i

Total number of prefixes 2

many 10xs

mohammedmahmoud Mon, 02/11/2008 - 00:28
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Hi Ali,

The "neighbor default-originate" command differs than the "default-information originate" command, the default route generated via the default-originate command is kind of considered a special case and is not submitted to the outbound route-map and also won't appear in the output of the "show ip bgp neighbors x.x.x.x advertised-routes", below is a summary of BGP default-route cases:

1. default-information originate + redistribute static (or any dynamic routing protocol having the default route - but the route must be present in the routing table using the redistributed protocol).

2. network command "network" but must make sure the default route is present in the routing table (most commonly with a static default route to null0 interface, accordingly any destination address that cannot be matched to a more-specific route matches the static route and is dropped).

3. Using the neighbor x.x.x.x default-originate command. This method does not require the presence of the network in the routing table of the advertising router (most commonly used in the cases where a default should be sent to some neighbors, but not to others).


Mohammed Mahmoud.


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