Hello Bird Users,

I am trying to implement RTBH (Remotely Triggered Black Hole) in below setup:

0.Simplified Topology:

• ebgp fabric
• inside fabric we use only IPv6, so we announce IPv4 blocks with IPv6 next hop (extended next hop)
• tor --- leaf --- spine---3xstem(3xborder_leaf) --- border
• tor announces 192.168.66.1/32 tagged with (65535,666) up to border

1.Border has static route:

r04.border01.labkrk05.fab> show route for  23.0.0.255

23.0.0.255/32        blackhole [DISCARD_ROUTE_v4 2024-01-08] * (200)

2.Border learns 192.168.66.1/32.  In import filter I change next hop to 23.0.0.255 to blackhole traffic to 192.168.66.1/32.

I don’t see this change in “show route”   but I see this in “show route all”

Can you give me a tip how to change eBGP next hop in this scenario and resolve it recursively via static route?

r04.border01.labkrk05.fab> show route  for 192.168.66.1/32

Executing "/usr/sbin/birdc show route for 192.168.66.1/32"

Table master4:

192.168.66.1/32      unicast [fc00:5:1:502::1__r01.stem01.la 09:24:07.174] * (100) [AS4290000010i]

                via fc00:5:1:502::1 on ae201

                     unicast [fc00:5:1:503::1__r02.stem01.la 09:24:07.174] (100) [AS4290000010i]

                via fc00:5:1:503::1 on ae202

                     unicast [fc00:5:1:504::1__r03.stem01.la 09:24:07.172] (100) [AS4290000010i]

                via fc00:5:1:504::1 on ae203

r04.border01.labkrk05.fab> show route  for 192.168.66.1/32 all

192.168.66.1/32      unicast [fc00:5:1:502::1__r01.stem01.la 09:24:07.174] * (100) [AS4290000010i]

                via fc00:5:1:502::1 on ae201

                Type: BGP univ

                BGP.origin: IGP

                BGP.as_path: 4290000004 4290000005 4290000008 4290000010

                BGP.next_hop: 23.0.0.255

                BGP.local_pref: 100

                BGP.community: (65535,666)

                     unicast [fc00:5:1:503::1__r02.stem01.la 09:24:07.174] (100) [AS4290000010i]

                via fc00:5:1:503::1 on ae202

                Type: BGP univ

                BGP.origin: IGP

                BGP.as_path: 4290000004 4290000006 4290000008 4290000010

BGP.next_hop: 23.0.0.255

                BGP.local_pref: 100

                BGP.community: (65535,666)

                     unicast [fc00:5:1:504::1__r03.stem01.la 09:24:07.172] (100) [AS4290000010i]

                via fc00:5:1:504::1 on ae203

                Type: BGP univ

                BGP.origin: IGP

                BGP.as_path: 4290000004 4290000007 4290000008 4290000010

BGP.next_hop: 23.0.0.255

                BGP.local_pref: 100

                BGP.community: (65535,666)

Regards,

Dariusz