Hello
I use Debian 8.9 / Quagga 0.99.23.1 (BGP / IBGP / OSPF). For iBGP / OSPF I use a dummy interface.
My AS is 10, my IP public block are 10.10.10.0/24
Debian1 : dummy0 = 10.10.10.1/32
Debian1 : eth0 = 192.168.1.1/30 (for ibgp/ospf)
router bgp 10
no synchronization
bgp router-id 10.10.10.1
bgp log-neighbor-changes
bgp always-compare-med
network 10.10.10.0 mask 255.255.255.0
neighbor 10.10.10.2 remote-as 10
neighbor 10.10.10.2 update-source dummy0
neighbor 10.10.10.2 next-hop-self
neighbor 10.10.10.2 soft-reconfiguration inbound
no auto-summary
!
router ospf
ospf router-id 10.10.10.1
passive-interface dummy0
network 10.10.10.0/24 area 0.0.0.0
network 192.168.1.0/30 area 0.0.0.0
!
-----------------------------------------
Debian2 : dummy1 = 10.10.10.2/32
Debian2 : eth0 = 192.168.1.2/30 (for ibgp/ospf)
router bgp 10
no synchronization
bgp router-id 10.10.10.2
bgp log-neighbor-changes
bgp always-compare-med
network 10.10.10.0 mask 255.255.255.0
neighbor 10.10.10.1 remote-as 10
neighbor 10.10.10.1 update-source dummy0
neighbor 10.10.10.1 next-hop-self
neighbor 10.10.10.1 soft-reconfiguration inbound
no auto-summary
!
router ospf
ospf router-id 10.10.10.2
passive-interface dummy0
network 10.10.10.0/24 area 0.0.0.0
network 192.168.1.0/30 area 0.0.0.0
!
The prefix 200.200.200.0/24 is shorter via Debian2. On Debian2 I can ping 200.200.200.1.
Since Debian1 I can not ping 200 200.200.1, yet it is well in the routing table:
Debian1# sh ip bgp 200.200.200.1
BGP routing table entry for 200.200.200.0/24
Paths: (2 available, best #1, table Default-IP-Routing-Table)
Not advertised to any peer
200
10.10.10.2 from 10.10.10.2 (10.10.10.2)
Origin IGP, metric 100, localpref 100, valid, internal, best
Last update: Sun Aug 13 14:07:39 2017
Debian1# sh ip route 200.200.200.1
Routing entry for 200.200.200.0/24
Known via "ospf", distance 200, metric 100, best
Last update 01:37:20 ago
10.10.10.2 (recursive)
* 192.168.1.2, via eth0
Since 200.200.200.1 with TCPDUMP the ping arrive from the private interconnection IP 192.168.1.2 and not from 10.10.10.1, why?
Thank you for your help
I use Debian 8.9 / Quagga 0.99.23.1 (BGP / IBGP / OSPF). For iBGP / OSPF I use a dummy interface.
My AS is 10, my IP public block are 10.10.10.0/24
Debian1 : dummy0 = 10.10.10.1/32
Debian1 : eth0 = 192.168.1.1/30 (for ibgp/ospf)
router bgp 10
no synchronization
bgp router-id 10.10.10.1
bgp log-neighbor-changes
bgp always-compare-med
network 10.10.10.0 mask 255.255.255.0
neighbor 10.10.10.2 remote-as 10
neighbor 10.10.10.2 update-source dummy0
neighbor 10.10.10.2 next-hop-self
neighbor 10.10.10.2 soft-reconfiguration inbound
no auto-summary
!
router ospf
ospf router-id 10.10.10.1
passive-interface dummy0
network 10.10.10.0/24 area 0.0.0.0
network 192.168.1.0/30 area 0.0.0.0
!
-----------------------------------------
Debian2 : dummy1 = 10.10.10.2/32
Debian2 : eth0 = 192.168.1.2/30 (for ibgp/ospf)
router bgp 10
no synchronization
bgp router-id 10.10.10.2
bgp log-neighbor-changes
bgp always-compare-med
network 10.10.10.0 mask 255.255.255.0
neighbor 10.10.10.1 remote-as 10
neighbor 10.10.10.1 update-source dummy0
neighbor 10.10.10.1 next-hop-self
neighbor 10.10.10.1 soft-reconfiguration inbound
no auto-summary
!
router ospf
ospf router-id 10.10.10.2
passive-interface dummy0
network 10.10.10.0/24 area 0.0.0.0
network 192.168.1.0/30 area 0.0.0.0
!
The prefix 200.200.200.0/24 is shorter via Debian2. On Debian2 I can ping 200.200.200.1.
Since Debian1 I can not ping 200 200.200.1, yet it is well in the routing table:
Debian1# sh ip bgp 200.200.200.1
BGP routing table entry for 200.200.200.0/24
Paths: (2 available, best #1, table Default-IP-Routing-Table)
Not advertised to any peer
200
10.10.10.2 from 10.10.10.2 (10.10.10.2)
Origin IGP, metric 100, localpref 100, valid, internal, best
Last update: Sun Aug 13 14:07:39 2017
Debian1# sh ip route 200.200.200.1
Routing entry for 200.200.200.0/24
Known via "ospf", distance 200, metric 100, best
Last update 01:37:20 ago
10.10.10.2 (recursive)
* 192.168.1.2, via eth0
Since 200.200.200.1 with TCPDUMP the ping arrive from the private interconnection IP 192.168.1.2 and not from 10.10.10.1, why?
Thank you for your help