BGP between R4 & R5 & R4 & BB3 keeps on flapping. Peer would come up for a min & then go down on alternate basis, never at the same time. Shared below is the bgp configuration for both the swicth. Peering is stable only in two condition
1. When I configure remote as for 155.1.45.4 as 100
2. Configure no bgp enforce-first-as.
Purpose of dual as to achieve peering with local as as well as real as but for some odd reason I am not able to achieve the same.
I have no clue why no bgp enforce-first-as solved the issue. I see no reason to use it here.
Cleared the session multiple times but no luck.
Error Received before a peer flap:
%BGP-5-ADJCHANGE: neighbor 155.1.45.4 Down BGP Notification sent
%BGP-3-NOTIFICATION: sent to neighbor 155.1.45.4 3/11 (invalid or corrupt AS path) 13 bytes 40020A02 04006400 36003200 3C
Rack1R5#
BGP: 155.1.45.4 Bad attributes FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF 0033 0200 0000 1840 0101 0040 020A 0204 0064 0036 0032 003C 4003 049B 012D 0408 7108 70
Rack1R5#
%BGP-3-NOTIFICATION: sent to neighbor 155.1.45.4 2/2 (peer in wrong AS) 2 bytes 0064
Rack1R5# FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF 002D 0104 0064 00B4 9601 0404 1002 0601 0400 0100 0102 0280 0002 0202 00
Rack1R5#sh run | sec bgp
router bgp 200
no synchronization
no bgp enforce-first-as
bgp log-neighbor-changes
bgp maxas-limit 200
network 5.5.5.0 mask 255.255.255.0
neighbor 155.1.0.2 remote-as 200
neighbor 155.1.0.2 route-reflector-client
neighbor 155.1.23.3 remote-as 200
neighbor 155.1.45.4 remote-as 146
neighbor 155.1.58.8 remote-as 200
neighbor 155.1.58.8 route-reflector-client
neighbor 155.1.108.10 remote-as 200
neighbor 155.1.108.10 route-reflector-client
no auto-summary
alias exec b show ip bgp summary
alias exec n show ip bgp nei
Rack1R4#sh run | sec bgp
router bgp 146
no synchronization
no bgp enforce-first-as
bgp log-neighbor-changes
bgp maxas-limit 50
neighbor 155.1.45.5 remote-as 200
neighbor 155.1.45.5 local-as 100 no-prepend replace-as dual-as
neighbor 155.1.146.1 remote-as 146
neighbor 204.12.1.254 remote-as 54
neighbor 204.12.1.254 local-as 100 no-prepend replace-as dual-as
no auto-summary
alias exec b show ip bgp summary
Rack1R5#show ip bgp reg _54_
BGP table version is 101, local router ID is 150.1.5.5
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
*> 28.119.16.0/24 155.1.45.4 0 100 54 i
* i 155.1.13.1 0 100 0 146 54 i
*> 28.119.17.0/24 155.1.45.4 0 100 54 i
* i 155.1.13.1 0 100 0 146 54 i
*> 112.0.0.0 155.1.45.4 0 100 54 50 60 i
* i 155.1.13.1 0 100 0 146 54 50 60 i
*> 113.0.0.0 155.1.45.4 0 100 54 50 60 i
* i 155.1.13.1 0 100 0 146 54 50 60 i
*> 114.0.0.0 155.1.45.4 0 100 54 i
* i 155.1.13.1 0 100 0 146 54 i
*> 115.0.0.0 155.1.45.4 0 100 54 i
* i 155.1.13.1 0 100 0 146 54 i
*> 116.0.0.0 155.1.45.4 0 100 54 i
* i 155.1.13.1 0 100 0 146 54 i
*> 117.0.0.0 155.1.45.4 0 100 54 i
* i 155.1.13.1 0 100 0 146 54 i
*> 118.0.0.0 155.1.45.4 0 100 54 i
* i 155.1.13.1 0 100 0 146 54 i
*> 119.0.0.0 155.1.45.4 0 100 54 i