IBGP routing issue

[aprasad11]

Hi Guys,

I have a issue with IBGP routing.  

The IBGP neighbors are up but i am not able to ping prefix advertised between R9 ad R10.

I am able to ping peering neighbors but not routes that are advertised through BGP

I may have missed out something? below is IBGP config, show output and ping.  

--------------------------------------------------------------------------------------------------------------

R10#show run | s router bgp
router bgp 34567
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 9.9.9.9 remote-as 34567
neighbor 9.9.9.9 update-source Loopback200
!
address-family ipv4
network 10.10.10.11 mask 255.255.255.255
neighbor 9.9.9.9 activate
exit-address-family

R10#show ip bgp
BGP table version is 3, local router ID is 123.10.10.10
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
*>i 9.9.9.1/32 9.9.9.9 0 100 0 i
*> 10.10.10.11/32 0.0.0.0 0 32768 i

---------------------------------------------------------------------------------------------------------------

R9#show run | s router bgp
router bgp 34567
bgp log-neighbor-changes
network 9.9.9.1 mask 255.255.255.255
neighbor 10.10.10.10 remote-as 34567
neighbor 10.10.10.10 update-source Loopback200

R9#show ip bg
BGP table version is 7, local router ID is 123.9.9.9
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
*> 9.9.9.1/32 0.0.0.0 0 32768 i
*>i 10.10.10.11/32 10.10.10.10 0 100 0 i

----------------------------------------------------------------------------------------------------------------

Ping result from R10

R10#ping 9.9.9.1 source 10.10.10.11
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 9.9.9.1, timeout is 2 seconds:
Packet sent with a source address of 10.10.10.11
.....
Success rate is 0 percent (0/5)
R10#

[Julio E. Moisa]

Hi 

It looks fine, could you please share: show ip bgp summary. I see you are using the loopback200 as update-source, what IGP are you using? Have you disabled the sync?

router bgp x
no sync

Thank you in advance. 

[aprasad11]

Hi Julio,

Below is output for show ip bgp summary. IGP that i am using is EIGRP and yes i have disabled syn.

R10(config-router)#do show ip bgp sum
BGP router identifier 123.10.10.10, local AS number 34567
BGP table version is 5, main routing table version 5
2 network entries using 280 bytes of memory
2 path entries using 160 bytes of memory
2/2 BGP path/bestpath attribute entries using 288 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 728 total bytes of memory
BGP activity 7/5 prefixes, 7/5 paths, scan interval 60 secs

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
9.9.9.9 4 34567 5 5 5 0 0 00:00:27 1

-------------------------------------------------------------------------------------------------

R9(config-router)#do show ip bg sum
BGP router identifier 123.9.9.9, local AS number 34567
BGP table version is 3, main routing table version 3
2 network entries using 280 bytes of memory
2 path entries using 160 bytes of memory
2/2 BGP path/bestpath attribute entries using 288 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 728 total bytes of memory
BGP activity 5/3 prefixes, 6/4 paths, scan interval 60 secs

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
10.10.10.10 4 34567 6 6 3 0 0 00:01:08 1

[Julio E. Moisa]

Thank you, please compare your configuration with mine. Also I have disabled auto-summary.

:-)

[aprasad11]

Hi Julio,

yes after disabling sync i have done a hard reset for bgp neighbours (clear ip bgp *)..

Still cannot ping 

R10#ping 9.9.9.1 source 10.10.10.11
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 9.9.9.1, timeout is 2 seconds:
Packet sent with a source address of 10.10.10.11
.....
Success rate is 0 percent (0/5)

[Julio E. Moisa]

Is possible to share the entire config? I changed the ip 10.10.10.11 instead 10.10.10.1

Are your routers connected directly like my example?

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.10.11, timeout is 2 seconds:
Packet sent with a source address of 9.9.9.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/10/12 ms
R9#

R10#ping 9.9.9.1 source 10.10.10.11

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 9.9.9.1, timeout is 2 seconds:
Packet sent with a source address of 10.10.10.11
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/12/20 ms
R10#

[aprasad11]

Hi Julio,

Attached is full config for R9 and R10.

Please note that i transit over two other eigrp routers SW3 and SW4

Thank You for your help

[Julio E. Moisa · Accepted solution]

Hi

Have simulated your configuration (just changing the ip addressing on the switches)

ROUTER 9

interface Loopback1
ip address 9.9.9.1 255.255.255.255
!
interface Loopback200
ip address 9.9.9.9 255.255.255.255
!
interface FastEthernet0/0
ip address 10.95.0.9 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
router eigrp 1
network 9.9.9.9 0.0.0.0
network 10.95.0.9 0.0.0.0
no auto-summary
!
router bgp 34567
no synchronization
bgp log-neighbor-changes
network 9.9.9.1 mask 255.255.255.255
neighbor 10.10.10.10 remote-as 34567
neighbor 10.10.10.10 update-source Loopback200
no auto-summary

SWITCH 1

nothing special

Vlan 10

ip routing

interface FastEthernet0/1
switchport access vlan 10
switchport mode access

!
interface FastEthernet0/3
no switchport
ip address 1.1.1.1 255.255.255.0
duplex auto
!
interface Vlan10
ip address 10.95.0.5 255.255.255.0
!
!
router eigrp 1
network 0.0.0.0
!

!

SWITCH 2

nothing special

vlan 20

ip routing

interface FastEthernet0/1
switchport access vlan 20
switchport mode access

!
interface FastEthernet0/3
no switchport
ip address 1.1.1.2 255.255.255.0
duplex auto
!
interface Vlan20
ip address 10.106.0.6 255.255.255.0
!
!
router eigrp 1
network 0.0.0.0

ROUTER 10

interface Loopback1
ip address 10.10.10.11 255.255.255.255
!
interface Loopback200
ip address 10.10.10.10 255.255.255.255
!
interface FastEthernet0/0
ip address 10.106.0.10 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
router eigrp 1
network 10.10.10.10 0.0.0.0
network 10.106.0.10 0.0.0.0
no auto-summary
!
router bgp 34567
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 9.9.9.9 remote-as 34567
neighbor 9.9.9.9 update-source Loopback200
!
address-family ipv4
neighbor 9.9.9.9 activate
no auto-summary
no synchronization
network 10.10.10.11 mask 255.255.255.255
exit-address-family

##########################################

##########################################

Now please note the routing tables

R9#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

1.0.0.0/24 is subnetted, 1 subnets
D 1.1.1.0 [90/307200] via 10.95.0.5, 00:13:34, FastEthernet0/0
9.0.0.0/32 is subnetted, 2 subnets
C 9.9.9.9 is directly connected, Loopback200
C 9.9.9.1 is directly connected, Loopback1
10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
D 10.10.10.10/32 [90/435456] via 10.95.0.5, 00:13:28, FastEthernet0/0
B 10.10.10.11/32 [200/0] via 10.10.10.10, 00:12:37
C 10.95.0.0/24 is directly connected, FastEthernet0/0
D 10.106.0.0/24 [90/307456] via 10.95.0.5, 00:13:35, FastEthernet0/0
R9#
R9#
R9#
R9#sh ip bgp
BGP table version is 3, local router ID is 9.9.9.9
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
*> 9.9.9.1/32 0.0.0.0 0 32768 i
*>i10.10.10.11/32 10.10.10.10 0 100 0 i
R9#

R10#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

1.0.0.0/24 is subnetted, 1 subnets
D 1.1.1.0 [90/307200] via 10.106.0.6, 00:14:23, FastEthernet0/0
9.0.0.0/32 is subnetted, 2 subnets
D 9.9.9.9 [90/435456] via 10.106.0.6, 00:14:23, FastEthernet0/0
B 9.9.9.1 [200/0] via 9.9.9.9, 00:13:32
10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
C 10.10.10.10/32 is directly connected, Loopback200
C 10.10.10.11/32 is directly connected, Loopback1
D 10.95.0.0/24 [90/307456] via 10.106.0.6, 00:14:23, FastEthernet0/0
C 10.106.0.0/24 is directly connected, FastEthernet0/0
R10#
R10#
R10#sh ip bg
R10#sh ip bgp
BGP table version is 3, local router ID is 10.10.10.11
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
*>i9.9.9.1/32 9.9.9.9 0 100 0 i
*> 10.10.10.11/32 0.0.0.0 0 32768 i
R10#

Now if you advertise the prefixes into EIGRP As John mentioned previously, it will be known via EIGRP and ping will be enabled:

R10#sh ip bgp
BGP table version is 4, local router ID is 10.10.10.11
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
r>i9.9.9.1/32 9.9.9.9 0 100 0 i      <---(r) indicates there is best path through IGP in this case EIGRP
*> 10.10.10.11/32 0.0.0.0 0 32768 i
R10#
R10#
R10#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

1.0.0.0/24 is subnetted, 1 subnets
D 1.1.1.0 [90/307200] via 10.106.0.6, 00:31:14, FastEthernet0/0
9.0.0.0/32 is subnetted, 2 subnets
D 9.9.9.9 [90/435456] via 10.106.0.6, 00:31:14, FastEthernet0/0
D 9.9.9.1 [90/435456] via 10.106.0.6, 00:01:06, FastEthernet0/0
10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
C 10.10.10.10/32 is directly connected, Loopback200
C 10.10.10.11/32 is directly connected, Loopback1
D 10.95.0.0/24 [90/307456] via 10.106.0.6, 00:31:16, FastEthernet0/0
C 10.106.0.0/24 is directly connected, FastEthernet0/0
R10#

Now if you want them known via BGP you should change the distance value lowest than 90 on both routers

Example:

ROUTER 10

router bgp 34567
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 9.9.9.9 remote-as 34567
neighbor 9.9.9.9 update-source Loopback200
!
address-family ipv4
neighbor 9.9.9.9 activate
distance bgp 20 89 20

R10#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

1.0.0.0/24 is subnetted, 1 subnets
D 1.1.1.0 [90/307200] via 10.106.0.6, 00:26:13, FastEthernet0/0
9.0.0.0/32 is subnetted, 2 subnets
D 9.9.9.9 [90/435456] via 10.106.0.6, 00:26:13, FastEthernet0/0
B 9.9.9.1 [89/0] via 9.9.9.9, 00:02:08
10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
C 10.10.10.10/32 is directly connected, Loopback200
C 10.10.10.11/32 is directly connected, Loopback1
D 10.95.0.0/24 [90/307456] via 10.106.0.6, 00:26:13, FastEthernet0/0
C 10.106.0.0/24 is directly connected, FastEthernet0/0
R10#

R10#ping 9.9.9.1 source 10.10.10.11 repeat 100

Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 9.9.9.1, timeout is 2 seconds:
Packet sent with a source address of 10.10.10.11
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (100/100), round-trip min/avg/max = 4/10/20 ms
R10#

[aprasad11]

Thanks Julio and Jon.. both answers were correct.

Thanks

[Julio E. Moisa]

It was a pleasure

Have a great day

:-)

[Julio E. Moisa]

Hi, this is my configuration, assuming R9 and R10 are connected directly, I have used EIGRP as my NLRI:

ROUTER 9

interface Loopback1
ip address 9.9.9.1 255.255.255.255
!
interface Loopback200
ip address 9.9.9.9 255.255.255.255
!
interface FastEthernet0/0
ip address 10.109.0.9 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
router eigrp 1
network 9.9.9.9 0.0.0.0
network 10.109.0.9 0.0.0.0
no auto-summary
!
router bgp 34567
no synchronization
bgp log-neighbor-changes
network 9.9.9.1 mask 255.255.255.255
neighbor 10.10.10.10 remote-as 34567
neighbor 10.10.10.10 update-source Loopback200
no auto-summary

ROUTER 10

interface Loopback1
ip address 10.10.10.1 255.255.255.255
!
interface Loopback200
ip address 10.10.10.10 255.255.255.255
!
interface FastEthernet0/0
ip address 10.109.0.10 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
router eigrp 1
network 10.10.10.10 0.0.0.0
network 10.109.0.10 0.0.0.0
no auto-summary
!
router bgp 34567
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 9.9.9.9 remote-as 34567
neighbor 9.9.9.9 update-source Loopback200
!
address-family ipv4
neighbor 9.9.9.9 activate
no auto-summary
no synchronization
network 10.10.10.1 mask 255.255.255.255
exit-address-family

And it works:

R9#sh ip bgp
BGP table version is 3, local router ID is 9.9.9.9
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
*> 9.9.9.1/32 0.0.0.0 0 32768 i
*>i10.10.10.1/32 10.10.10.10 0 100 0 i
R9#
R9#
R9#
R9#ping 10.10.10.1 source 9.9.9.1 repeat 10

Type escape sequence to abort.
Sending 10, 100-byte ICMP Echos to 10.10.10.1, timeout is 2 seconds:
Packet sent with a source address of 9.9.9.1
!!!!!!!!!!
Success rate is 100 percent (10/10), round-trip min/avg/max = 8/10/16 ms
R9#

################

R10#sh ip bg
R10#sh ip bgp
BGP table version is 3, local router ID is 10.10.10.10
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
*>i9.9.9.1/32 9.9.9.9 0 100 0 i
*> 10.10.10.1/32 0.0.0.0 0 32768 i
R10#
R10#
R10#
R10#ping 9.9.9.1 source 10.10.10.1 repeat 10

Type escape sequence to abort.
Sending 10, 100-byte ICMP Echos to 9.9.9.1, timeout is 2 seconds:
Packet sent with a source address of 10.10.10.1
!!!!!!!!!!
Success rate is 100 percent (10/10), round-trip min/avg/max = 4/10/16 ms
R10#

Hope it is useful

:-)

[aprasad11]

Hi Julio,

directly connected works fine with me too but i only get issues when i transit through the other two eigrp neighbours (SW3 and SW4).. probably i need to check the IGP?

[Julio E. Moisa]

Hi

Yes, I was checking your config and it looks good, Which models are SW3 and 4? just make the following test

configure the EIGRP on the switches:

conf t

no router eigrp 34567

router eigrp 34567
no auto-summary
network 0.0.0.0 255.255.255.255

on both switches.

[Jon Marshall · Accepted solution]

You are not advertising 9.9.9.1 or 10.10.10.11 into EIGRP so when the ping gets to the intermediate switches they have no route to those IPs.

Jon