[c-nsp] NXOS BFD sends packets sourced and destined for it's own IP address to the remote host.

[Drew Weaver]

Ah okay, I suppose I was confused because I didn't configure bfd echo on the Nexus side and it's not anywhere in the configuration on the device.


-----Original Message-----
From: Gert Doering <gert at greenie.muc.de> 
Sent: Monday, January 18, 2021 4:26 PM
To: Drew Weaver <drew.weaver at thenap.com>
Cc: 'cisco-nsp at puck.nether.net' <cisco-nsp at puck.nether.net>
Subject: Re: [c-nsp] NXOS BFD sends packets sourced and destined for it's own IP address to the remote host.

Hi,

On Mon, Jan 18, 2021 at 08:15:02PM +0000, Drew Weaver wrote:
> I can really easily resolve this by just adding another line to the ACL but I would much rather understand how this traffic is ending up on the wire in the first place.

By being sent out, to be returned by the other end "if its IP forwarding engine is working" - BFD echo mode

  https://netcraftsmen.com/clarifying-bfd-and-bfd-echo/

gert
--
"If was one thing all people took for granted, was conviction that if you  feed honest figures into a computer, honest figures come out. Never doubted  it myself till I met a computer with a sense of humor."
                             Robert A. Heinlein, The Moon is a Harsh Mistress

Gert Doering - Munich, Germany                             gert at greenie.muc.de