anyone use fbtracert successfully?

Wed Nov 24 17:47:49 UTC 2021

I have used it successfully in a test environment that I was using ECMP in.
Most of the public networks that I've worked with don't use ECMP as often
as other methods for steering traffic (LAGs, BGP MEDs, etc).

What I have seen it fantastically useful for was troubleshooting a transit
provider, or for when they were congested or had a flapping core link.
Granted I *think *it's still subject to ICMP deprioritization (most SP's
use it prodigiously), and most MPLS cores don't decrement TTL, but it was
still useful to be able to show them "no, at this IP, I *always* drop
traffic, when..."

- Thomas Scott | mr.thomas.scott at gmail.com

On Wed, Nov 24, 2021 at 12:23 PM Adam Thompson <athompson at merlin.mb.ca>
wrote:

> The tool fbtracert (http://github.com/facebookarchive/fbtracert) was
> mentioned here recently as a way to get visibility into multi-pathing.
>
> Has anyone here ever used this tool successfully?
>
>
>
> Supposedly Facebook uses this tool internally, but… that doesn’t help much.
>
>
>
> I’ve tried it on 4 different platforms/OSes (WSL Ubuntu; RedHat; Debian;
> OpenBSD), and versions of Go (v1.10 through v1.16), in three very different
> environments (on-prem public IP; on-prem NAT’d; cloud public IP), and I’ve
> yet to see it produce any meaningful output – each run/iteration/thread
> only detects one, single, hop out of the entire chain of routers, making it
> less than useful.  Granted, that’s not a full regression test by any means,
> but if anyone here has ever used it successfully, could you please let me
> know what sort of environment you ran it in/on?
>
>
>
> Thanks,
>
> -Adam
>
>
>
> *Adam Thompson*
> Consultant, Infrastructure Services
> [image: 1593169877849]
> 100 - 135 Innovation Drive
> Winnipeg, MB, R3T 6A8
> (204) 977-6824 or 1-800-430-6404 (MB only)
> athompson at merlin.mb.ca
> www.merlin.mb.ca
>
>
>
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