BGP route advertised but cannot ping loopback

[elpablito]

I'm preparing myself for new CCNP exam and working on a lab where I have 5 routers running BGP, R1 advertises network 192.168.20.0 and the Loopback1 is 192.168.20.1. Route is advertised and installed in the routing table but I cannot ping loopback int 192.168.20.1 from other routers other than directly connected R2.

R1:

router bgp 100
bgp log-neighbor-changes
network 192.168.20.0
neighbor 11.1.1.2 remote-as 300

R2:

router bgp 300
bgp log-neighbor-changes
network 100.10.2.0 mask 255.255.255.0
network 200.0.0.0
network 201.0.0.0
network 202.0.0.0
aggregate-address 200.0.0.0 252.0.0.0 summary-only
neighbor 11.1.1.1 remote-as 100
neighbor 22.2.2.2 remote-as 300
neighbor 55.5.5.2 remote-as 500

R5:

router bgp 500
bgp log-neighbor-changes
network 100.10.5.0 mask 255.255.255.0
neighbor 44.4.4.1 remote-as 400
neighbor 55.5.5.1 remote-as 300
neighbor 66.6.6.1 remote-as 300

IP route

R2

11.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        11.1.1.0/30 is directly connected, Ethernet0/1
L        11.1.1.2/32 is directly connected, Ethernet0/1
      22.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        22.2.2.0/30 is directly connected, Ethernet0/0
L        22.2.2.1/32 is directly connected, Ethernet0/0
      55.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        55.5.5.0/30 is directly connected, Ethernet0/2
L        55.5.5.1/32 is directly connected, Ethernet0/2
      100.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
C        100.10.2.0/24 is directly connected, Loopback1
L        100.10.2.254/32 is directly connected, Loopback1
B        100.10.3.0/24 [200/0] via 22.2.2.2, 09:53:58
B        100.10.4.0/24 [200/0] via 22.2.2.2, 06:38:53
B        100.10.5.0/24 [20/0] via 55.5.5.2, 09:53:58
      172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
C        172.16.1.0/24 is directly connected, Loopback0
L        172.16.1.2/32 is directly connected, Loopback0
B     192.168.20.0/24 [20/0] via 11.1.1.1, 03:13:43
B     200.0.0.0/6 [200/0] via 0.0.0.0, 09:41:47, Null0
      200.0.0.0/24 is variably subnetted, 2 subnets, 2 masks
C        200.0.0.0/24 is directly connected, Loopback5
L        200.0.0.1/32 is directly connected, Loopback5
      201.0.0.0/24 is variably subnetted, 2 subnets, 2 masks
C        201.0.0.0/24 is directly connected, Loopback6
L        201.0.0.1/32 is directly connected, Loopback6
      202.0.0.0/24 is variably subnetted, 2 subnets, 2 masks
C        202.0.0.0/24 is directly connected, Loopback7
L        202.0.0.1/32 is directly connected, Loopback7

R5:

      44.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        44.4.4.0/30 is directly connected, Ethernet0/0
L        44.4.4.2/32 is directly connected, Ethernet0/0
      55.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        55.5.5.0/30 is directly connected, Ethernet0/2
L        55.5.5.2/32 is directly connected, Ethernet0/2
      66.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        66.6.6.0/30 is directly connected, Ethernet0/1
L        66.6.6.2/32 is directly connected, Ethernet0/1
      100.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
B        100.10.2.0/24 [20/0] via 55.5.5.1, 09:46:28
B        100.10.3.0/24 [20/0] via 66.6.6.1, 09:47:30
B        100.10.4.0/24 [20/0] via 44.4.4.1, 09:56:01
C        100.10.5.0/24 is directly connected, Loopback1
L        100.10.5.254/32 is directly connected, Loopback1
      172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
C        172.16.1.0/24 is directly connected, Loopback0
L        172.16.1.5/32 is directly connected, Loopback0
B     192.168.20.0/24 [20/0] via 55.5.5.1, 03:06:14
B     200.0.0.0/6 [20/0] via 55.5.5.1, 09:34:18

[Giuseppe Larosa]

Hello @elpablito ,

in order for ping to work a return path is needed when you ping 192.168.20.1 from R5 r5 will use a source IP address of 55.5.5.2 but this subnet is not advertised in BGP by R2

on R2:

router bgp 300

network 55.5.5.0 mask 255.255.255.252

In this way R1 knows how to send the ICMP echo reply to 55.5.5.2

Hope to help

Giuseppe

[Martin L]

Ping is 2-way thing; you must have source in routing table at destination; so  usually BGP ping fails unless you do extended ping with source that has been advertised. 

what was ping command and try with ping x source y

Regards, ML
**Please Rate All Helpful Responses **

[paul driver]

Hello
When you say other rtrs othe than rtr 2 I see you have ibgp peering and are also aggregating advertised networks.However on the bgp aggregation you are not specifying the as-set feature and by default on bgp aggregation some prefixes could be suppressed due to the AS domains that these prefixes have originated are not being advertised.
Also as you have ibgp peering as such  the ebgp/ibgp rtrs should advertise themselves as the next-hop for any ebgp prefixes they advertise towards any ibgp peers because if this isn't done then any ebgp routes would be advertised to those ibgp peers with the ebgp rtrs as the next hop ip address and if the ibgp rtrs dont have any reachability too these ebgp rtrs then next hop connectivity will fail.

Suggest the following and test again:

R2: < ebgp/ibgp rtr>
router bgp 300
aggregate-address 200.0.0.0 252.0.0.0 summary-only as-set
neighbor 22.2.2.2 next-hop-self