Hello,
Working on the simulation to show how BGP network x.x.x.x backdoor is working. So in the below example i have router which is configured with backdoor, when IGP (OSPF) is running i see this route in routing table, but from curiosity i shut that link to see if my route (172.16.3.0) will show up in bgp table. It is not showing up? My understanding of the backdoor is that it will be advertised to eBGP peers once IGP link go down, also this is local subnet to this router so i imagined that would be advertised right away?
R7#sh run | s bgp
router bgp 3
bgp router-id 192.168.3.254
bgp log-neighbor-changes
network 172.16.1.0 mask 255.255.255.0
network 172.16.3.0 mask 255.255.255.0 backdoor
network 172.17.0.0
network 192.168.6.128 mask 255.255.255.128
neighbor 10.255.255.3 remote-as 1
neighbor 10.255.255.3 ebgp-multihop 2
neighbor 10.255.255.3 update-source Loopback0
neighbor 10.255.255.3 filter-list 1 out
neighbor 192.168.100.38 remote-as 4
neighbor 192.168.100.38 filter-list 1 out
neighbor 192.168.100.42 remote-as 5
neighbor 192.168.100.42 filter-list 1 out
R7#sh ip bgp nei 10.255.255.3 adver
R7#sh ip bgp nei 10.255.255.3 advertised-routes
BGP table version is 13, local router ID is 192.168.3.254
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
*> 172.16.1.0/24 0.0.0.0 0 32768 i
*> 172.17.0.0 0.0.0.0 0 32768 i
*> 192.168.6.128/25 0.0.0.0 0 32768 i
Total number of prefixes 3
R7#
R7#sh ip int br | e una
Interface IP-Address OK? Method Status Protocol
Ethernet0/0 192.168.100.37 YES manual up up
Serial2/0 192.168.100.26 YES manual up up
Serial2/1 192.168.100.41 YES manual up up
Loopback0 10.255.255.7 YES manual up up
Loopback1 172.16.1.1 YES manual up up
Loopback3 172.16.3.1 YES manual up up
Loopback10 192.168.6.129 YES manual up up
Loopback11 172.17.0.1 YES manual up up
