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BGP "illegal network" when IPv6 default-originate

akshaypb6
Beginner
Beginner

Hi Team,

When I am trying to create BGP session with Router A to Router B the IPv6 session is not getting established.

In Router A, i have created the session in Global routing table and in Router B, i have used VRF.
For IPv4 and IPv6 Session from Router a, i will be only advertising default route using default-originate.

 

After removing the default-originate, the session is getting etsablished

 

In router B, we could observe the below logs 

 

RP/0/RP0/CPU0:2022 Mar 14 03:03:54.430 JST: bgp[1073]: %ROUTING-BGP-5-ADJCHANGE_DETAIL : neighbor 240b:c0e1:2550::2111:1:6a Down - BGP Notification sent, illegal network (VRF: A ; AFI/SAFI: 1/1) (AS: 12345)

Router A 

Global routing table 

IOS 7.3.2 

NCS 5504

 

Router B

VRF -A

IOS 7.3.2 

NCS 55A1

 

The config in Router A is as follows

 

router bgp 12345 neighbor-group BLEAF-V6
router bgp 12345 neighbor-group BLEAF-V6 remote-as 65301
router bgp 12345 neighbor-group BLEAF-V6 bfd fast-detect
router bgp 12345 neighbor-group BLEAF-V6 bfd multiplier 3
router bgp 12345 neighbor-group BLEAF-V6 bfd minimum-interval 300
router bgp 12345 neighbor-group BLEAF-V6 timers 60 180
router bgp 12345 neighbor-group BLEAF-V6 address-family ipv4 unicast
router bgp 12345 neighbor-group BLEAF-V6 address-family ipv4 unicast route-policy PASS-ALL in
router bgp 12345 neighbor-group BLEAF-V6 address-family ipv4 unicast route-policy DROP-ALL out
router bgp 12345 neighbor-group BLEAF-V6 address-family ipv4 unicast default-originate
router bgp 12345 neighbor 240b:c0e1:2550::2111:1:6b use neighbor-group BLEAF-V6

 

Kindly support to check this . Thanks in advance 

 

Regards,
Akshay

 

4 Replies 4

MHM Cisco World
Advisor
Advisor

Neighbor reach via ipv6 but you config it under address family ipv4.

paul driver
VIP Expert VIP Expert
VIP Expert

Hello

You mention ipv4/ ipv6 bgp peering but you dont show any ipv4 neighbour statements

 

Regards default route- are you saying when you remove an ipv4 default route thr bgp ipv4 peering establishes?

 

Note by design bgp peering will not establish if you are try to peer to a rtr using just a default route.


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Kind Regards
Paul

Harold Ritter
Cisco Employee
Cisco Employee

Hi @akshaypb6 ,

 

Can you please provide the BGP configuration for Router B?

 

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

JimWicks
Beginner
Beginner

at a minimum you'll need to provide the output from "show run router bgp" from both A & B devices.

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