Hello All,
We have two links from two different ISPs on BGP. Both links are connected on different CE router at our end. Network diagram attached for reference.
We are advertising two pools on this links , 192.168.10.0/24 from one ISP and 192.168.30.0/24 from other ISP.
Couple of days back we have experienced a problem during outage of ISP-1 link. We were not able to access pool advertised on ISP-1. Failover to second ISP was also not happened.
Requesting to help to validate the BGP configuration and suggest where might be the problem, so that we can fix the same and failover to either of the ISP can happen smoothly.
Also, if please anyone can help me the understand the configuration on BGP, as bit confused what exactly happened the time of failover so that IP were not reachable from outside.
Configuration is below.
ISP-1
router bgp 200
no bgp log-neighbor-changes
network 192.168.10.0 mask 255.255.255.0
network 192.168.30.0 mask 255.255.255.0
neighbor 172.16.1.1 remote-as 100
neighbor 172.16.1.1 next-hop-self
neighbor 172.16.1.1 soft-reconfiguration inbound
neighbor 172.16.1.1 route-map AS_PREP out
neighbor 172.16.1.1 maximum-prefix 50000 50
neighbor 172.16.1.1 filter-list 10 out
neighbor 192.168.10.3 remote-as 200
neighbor 192.168.10.3 version 4
neighbor 192.168.10.3 next-hop-self
neighbor 192.168.10.3 soft-reconfiguration inbound
neighbor 192.168.10.3 prefix-list default out
neighbor 192.168.10.3 maximum-prefix 25000 50
ip as-path access-list 1 permit ^100$
ip as-path access-list 10 permit ^$
ip prefix-list LAN1 seq 5 permit 192.168.30.0/24
!
ip prefix-list LAN2 seq 5 permit 192.168.10.0/24
!
ip prefix-list block seq 5 deny 0.0.0.0/0 ge 1
!
ip prefix-list default seq 5 permit 0.0.0.0/0
route-map WAN_OUT permit 10
match as-path 10
!
route-map AS_PREP permit 10
match ip address prefix-list LAN1
set as-path prepend 200 200 200 200 200
!
route-map AS_PREP permit 20
ip route 0.0.0.0 0.0.0.0 172.16.1.1 name ISP-1
interface GigabitEthernet0/0
description ISP-1 Link
ip address 172.16.1.1 255.255.255.252
ip access-group 100 in
ip access-group 100 out
no ip redirects
no ip unreachables
no ip proxy-arp
ip accounting output-packets
ip flow ingress
ip flow egress
duplex auto
speed auto
no cdp enable
interface GigabitEthernet0/1
description *** Conected to LAN **
ip address 192.168.30.2 255.255.255.0 secondary
ip address 192.168.10.2 255.255.255.0
no ip redirects
no ip unreachables
no ip proxy-arp
standby 1 ip 192.168.10.1
standby 1 timers 5 15
standby 1 priority 110
standby 1 preempt
duplex auto
speed auto
no cdp enable
+++++++++++
ISP-2 :-
router bgp 200
no bgp log-neighbor-changes
network 192.168.10.0 mask 255.255.255.0
network 192.168.30.0 mask 255.255.255.0
neighbor 192.168.10.2 remote-as 200
neighbor 192.168.10.2 version 4
neighbor 192.168.10.2 next-hop-self
neighbor 192.168.10.2 soft-reconfiguration inbound
neighbor 192.168.10.2 prefix-list default out
neighbor 192.168.10.2 maximum-prefix 25000 50
neighbor172.16.100.1 remote-as 300
neighbor172.16.100.1 next-hop-self
neighbor172.16.100.1 soft-reconfiguration inbound
neighbor172.16.100.1 route-map AS_PREP out
neighbor172.16.100.1 maximum-prefix 50000 50
neighbor172.16.100.1 filter-list 10 out
ip as-path access-list 1 permit ^300$
ip as-path access-list 10 permit ^$
ip prefix-list LAN1 seq 5 permit 192.168.30.0/24
!
ip prefix-list LAN2 seq 5 permit 192.168.10.0/24
!
ip prefix-list block seq 5 deny 0.0.0.0/0 ge 1
!
ip prefix-list default seq 5 permit 0.0.0.0/0
route-map WAN_OUT permit 10
match as-path 10
!
route-map AS_PREP permit 10
match ip address prefix-list LAN2
set as-path prepend 200 200 200 200 200
!
route-map AS_PREP permit 20
ip route 0.0.0.0 0.0.0.0 172.16.1.1 name Default
interface GigabitEthernet0/0
description ISP-2 Link
ip address 192.168.30.3 255.255.255.0 secondary
ip address 192.168.10.3 255.255.255.0
no ip redirects
no ip unreachables
no ip proxy-arp
standby 1 ip 192.168.10.1
standby 1 timers 5 15
standby 1 preempt
duplex auto
speed auto
no cdp enable
!
interface GigabitEthernet0/1
description *** Connected to LAN ***
ip address 172.16.100.2 255.255.255.252
no ip redirects
no ip unreachables
no ip proxy-arp
ip flow ingress
ip flow egress
duplex auto
speed auto
no cdp enable
Regards
JN
