nanog mailing list archives

Re: Cisco Nexus 3k Route Selection\Packet Forwarding Debugging


From: Mike Hammett <nanog () ics-il net>
Date: Mon, 3 Apr 2023 07:47:07 -0500 (CDT)

It shows the desired result. 




----- 
Mike Hammett 
Intelligent Computing Solutions 
http://www.ics-il.com 

Midwest-IX 
http://www.midwest-ix.com 

----- Original Message -----

From: "Jay Hennigan" <jay () west net> 
To: nanog () nanog org 
Sent: Monday, April 3, 2023 1:02:42 AM 
Subject: Re: Cisco Nexus 3k Route Selection\Packet Forwarding Debugging 

On 4/2/23 22:21, Mike Hammett wrote: 
We have a Nexus 3064 that is setup with partial BGP tables and is 
routing based on that. 


I've done a show ip bgp for an IP of interest and it has an expected 
next hop IP. I show ip arp on that next hop IP and it has the expected 
interface. 


However, sFlows show the packets leaving on a different interface, the 
one that would carry the default route for routes not otherwise known. 


If the next hop IP is expected and the ARP of that next hop IP is 
expected, why are packets leaving out an unexpected interface? 

Another route to the destination from a routing protocol with a lower 
distance? 

What does "show ip route [destination]" look like? 

-- 
Jay Hennigan - jay () west net 
Network Engineering - CCIE #7880 
503 897-8550 - WB6RDV 



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