Redistribution
BGP 0/0 into IGP
How can one redistribute an iBGP learned default-route (0.0.0.0/0) into an IGP (EIGRP/OSPF/IS-IS)?
The redistribution of iBGP routes into an IGP (EIGRP/OSPF/IS-IS) – can cause routing loops within the Autonomous System, which is not recommended. Hence iBGP redistribution into IGP is disabled by default. Use the bgp redistribute-internal command to enable redistribution of iBGP routes into IGPs. Note that the command is BGP specific and thus will enable default-route redistribution into any IGP redistributing BGP.
Precautions should be taken to redistribute specific routes using route-maps into an IGP. A sample configuration for redistributing an iBGP learned default route 0.0.0.0/0 into EIGRP is shown in this output. Configurations for OSPF/IS-IS are similar.
router bgp 65345
…
bgp redistribute-internal
!
router eigrp 10
…
redistribute bgp 65345 route-map check-def
!
ip prefix-list def-route seq 5 permit 0.0.0.0/0
!
route-map check-def permit 10
_match ip address prefix-list def-route
I found the above here.
Redistribution Terminology
area range
– Used to consolidate and summarise at an ABR
default-metric
– Sets the (default) metrics for routes redistributed into EIGRP, BGP, OSPF and RIP (others aren’t relevant to the CCIE RS track)
distribute-list in
– Used to filter received routes before they’re put in a database or failing a DB the routing table
distribute-list out
– Used to filter routes from sent routing updates
summary-address
– Used to create aggregate routes for OSPF (and IS-IS 😉 ), can specify whether to send out the subnets of the aggregate or not.
One Response to “Redistribution”
Haven’t checked with other protocols, but with OSPF ‘default-originate’ on any router except nssa-abr will give you same result and with RIP you have another alternative of permitting redistribution of iBGP – use route-map and apply metric (by default it gets 16).
Care to comment?