Re: IPv6 connectivity to mx[1-4].smtp.goog.

[Christopher Morrow]

On Tue, Feb 27, 2024 at 12:03 PM 𝑀𝒶𝓇𝒸𝑜 𝒟𝒶𝓋𝒾𝒹𝓈 via NANOG
 wrote:
>
> Op 27-02-24 om 16:22 schreef Brotman, Alex:
>
> > We are seeing the same,
>
> Thanks.
>
> > You may also want to ask the mailop list.
>
>
> I was about to do that, when I noticed that the problem seems solved.

sorry about the noise.

Re: IPv6 connectivity to mx[1-4].smtp.goog.

[𝑀𝒶𝓇𝒸𝑜 𝒟𝒶𝓋𝒾𝒹𝓈 via NANOG]

Op 27-02-24 om 16:22 schreef Brotman, Alex:


We are seeing the same,


Thanks.


You may also want to ask the mailop list.



I was about to do that, when I noticed that the problem seems solved.

--
𝑀𝒶𝓇𝒸𝑜

RE: IPv6 connectivity to mx[1-4].smtp.goog.

[Brotman, Alex via NANOG]

We are seeing the same, but seems like it's mostly affecting delivery for 
broadcom.com, and a few other smaller domains.  However, connectivity to the MX 
listed by gmail.com (and most other domains using GSuite, etc) are working fine 
over IPv6.

You may also want to ask the mailop list.

-- 
Alex Brotman
Sr. Engineer, Anti-Abuse & Messaging Policy
Comcast
 

> -Original Message-
> From: NANOG 
> On Behalf Of Marco Davids (Private) via NANOG
> Sent: Tuesday, February 27, 2024 8:03 AM
> To: nanog@nanog.org
> Subject: IPv6 connectivity to mx[1-4].smtp.goog.
> 
> Hi,
> 
> At
> https://urldefense.com/v3/__https://internet.nl__;!!CQl3mcHX2A!Dc9AZo4F
> nrpVmuo3Ehg5iQUAd4uTAsCdz9MWYKJqFWyWK7_XnaDnWN3_DkOAVq2e5
> CXVOb2triASeebvdg$  we're seeing IPv6 connection issues on TCP port
> 25 (SMTP) to mx[1-4].smtp.goog.
> 
> Either 100% DROP (so no TCP connection) or ⅔ failure to setup connection.
> 
> Further testing seems to confirm the problem is bigger and on Google's side.
> 
> So, this fails:
> 
> echo 'quit' | nc -6 -w 3 mx1.smtp.goog. 25
> 
> and this works:
> 
> echo 'quit' | nc -4 -w 3 mx1.smtp.goog. 25
> 
> (on MacOS use -G instead of -w)
> 
> Is anyone else seeing this? Any idea what is causing this?
> 
> --
> Marco

IPv6 connectivity to mx[1-4].smtp.goog.

[Marco Davids (Private) via NANOG]

Hi,

At https://internet.nl we're seeing IPv6 connection issues on TCP port 
25 (SMTP) to mx[1-4].smtp.goog.


Either 100% DROP (so no TCP connection) or ⅔ failure to setup connection.

Further testing seems to confirm the problem is bigger and on Google's side.

So, this fails:

echo 'quit' | nc -6 -w 3 mx1.smtp.goog. 25

and this works:

echo 'quit' | nc -4 -w 3 mx1.smtp.goog. 25

(on MacOS use -G instead of -w)

Is anyone else seeing this? Any idea what is causing this?

--
Marco