How "Allow Redistribute Default Route" Works on BGP and OSPF
Symptom
There are circumstances where routers need to advertise default routes to its peers . This document illustrates how we redistribute default routes to peer with/without having the default route in the routing table of the box.
Environment
- Any Firewall
Resolution
Enabling the "Allow Redistribute Default Route" with the redistribution profile having the default route is mandatory to have the default route advertised to its peers. The procedure is same for OSPF and BGP.
If the default route is not available on the routing table , you can directly add the default route(0.0.0.0/0) in the redistribution profile of the protocols in the BGP-Network--BGP---Redistribution profile, Network--OSPF--Exportrule and enable the Allow redistribute default route tab and distribute the route.
The significance of having the Allow Redistribute default route tab is to validate whether the default route needs to be propogated even if it is part of the redistribution profile, which has all the routes including default.
Troubleshooting - CLI
To check if the default route is propogated , check the following CLI commands
OSPF
> show routing protocol ospf dump lsbd 1 1.1.1.1 0.0.0.0/0 type-5 (External) 0x80000001 0x0000CEFE 29 Options: [External] Mask 0.0.0.0, type 2, tos 0 metric: 1, forward 0.0.0.0, tag 0.0.0.0
BGP
> show routing protocol bgp rib-out | match 0.0.0.0/0 0.0.0.0/0 10.46.40.1 peer-110 0.0.0.0 advertised no aggregation 65001 0.0.0.0/0 10.46.40.1 subint-2 0.0.0.0 advertised no aggregation 65001 0.0.0.0/0 10.46.40.1 tunnelpeer 0.0.0.0 advertised no aggregation 65001
Troubleshooting - WebGUI
For BGP, the same information can be checked on the WebGUI as well, but not for OSPF. This is found in the Virtual Router > BGP > RIB Out screen.