(An Untitled Masterwork)
ActivePublic
Actions

Authored by cmooney on Mar 30 2023, 10:35 AM.

Tags

None

Referenced Files

	F36934096: raw-paste-data.txt
	Mar 30 2023, 10:36 AM

	F36934095: raw-paste-data.txt
	Mar 30 2023, 10:36 AM

	F36934092: raw-paste-data.txt
	Mar 30 2023, 10:35 AM

Subscribers

None

	# R1 learning eBGP route with next-hop of the peer:

	root@r1> show bgp summary
	Threading mode: BGP I/O
	Groups: 1 Peers: 1 Down peers: 0
	Table Tot Paths Act Paths Suppressed History Damp State Pending
	inet.0
	1 1 0 0 0 0
	Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State\|#Active/Received/Accepted/Damped...
	80.231.152.77 6453 4 3 0 0 22 Establ
	inet.0: 1/1/1/0

	root@r1>


	root@r1> show route protocol bgp terse table inet.0

	inet.0: 11 destinations, 11 routes (11 active, 0 holddown, 0 hidden)
	+ = Active Route, - = Last Active, * = Both

	A V Destination P Prf Metric 1 Metric 2 Next hop AS path
	* ? 0.0.0.0/0 B 170 100 6453 I
	unverified >80.231.152.77


	# Route on the advertising router:

	root@tata> show route 0.0.0.0/0 terse exact table inet.0

	inet.0: 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden)
	+ = Active Route, - = Last Active, * = Both

	A V Destination P Prf Metric 1 Metric 2 Next hop AS path
	* ? 0.0.0.0/0 S 5 >172.20.20.1


	# Make this change on the advertising router:

	set protocols bgp group R1 multihop no-nexthop-change

	# Then back on R1:

	root@r1> show route protocol bgp terse table inet.0 hidden

	inet.0: 11 destinations, 11 routes (10 active, 0 holddown, 1 hidden)
	+ = Active Route, - = Last Active, * = Both

	A V Destination P Prf Metric 1 Metric 2 Next hop AS path
	? 0.0.0.0/0 B 6453 I
	unverified >172.20.20.1


	## Interestingly JunOS keeps the roote 'hidden'. This was unexpected, cos R1 is also connected to the 172.20.20.0/24 nextwork, so the next-hop should still be reachable. But looking:

	root@r1> show route protocol bgp extensive hidden

	inet.0: 11 destinations, 11 routes (10 active, 0 holddown, 1 hidden)
	0.0.0.0/0 (1 entry, 0 announced)
	BGP
	Next hop type: Router, Next hop index: 0
	Address: 0x55747cee9ddc
	Next-hop reference count: 1
	Source: 80.231.152.77
	Next hop: 172.20.20.1 via eth1, selected
	Session Id: 0x0
	State: <Hidden Ext Changed>
	Local AS: 48635 Peer AS: 6453
	Age: 9:48
	Validation State: unverified
	Task: BGP_6453.80.231.152.77
	AS path: 6453 I
	Router ID: 80.231.152.77
	Hidden reason: protocol nexthop is not on the interface


	Seems it won't insert it in routing table cos next-hop is on a different interface than the peering. I'm sure there is a way to change this behaviour, and won't be a thing with the K8 hosts. But anyway just noting.

Event Timeline

cmooney created this paste.Mar 30 2023, 10:35 AM

cmooney edited the content of this paste. (Show Details)

(An Untitled Masterwork)ActivePublicActions

Event Timeline

(An Untitled Masterwork)
ActivePublic
Actions