[gnu.org #1448007] Illegal command pipelining by lists.gnu.org (209.51.188.17)

[Ian Kelling via RT]

On Sat Nov 09 09:16:05 2019, address@hidden wrote:
> Hi, I ran into a problem while trying to subscribe to bug-gnu-emacs. My 
> subscription confirmations weren't coming through. I checked the mail 
> logs, and the root cause seems to be that lists.gnu.org (209.51.188.17)
> is being rejected by postfix's "postscreen_pipelining_enable = yes" 
> check, which looks for incorrect SMTP implementations. We have this 
> enabled on our MX to deter some spam bots.
> 
> The relevant feature is described at,
> 
>    http://www.postfix.org/POSTSCREEN_README.html#pipelining
> 
> And my logs for one of the sessions:
> 
>    Nov  9 08:18:19 mx1 postfix/postscreen[10830]: NOQUEUE: reject: RCPT
>    from [209.51.188.17]:40601: 450 4.3.2 Service currently unavailable;
>    from=<bug-gnu-emacs-bounces+michael=address@hidden>,
>    to=<address@hidden>, proto=ESMTP, helo=<lists.gnu.org>
> 
>    Nov  9 08:18:19 mx1 postfix/postscreen[10830]: COMMAND PIPELINING from
>    [209.51.188.17]:40601 after BDAT: Received: from localhost([::1]:36782
>    helo=lists1p.gnu.org)\r\n\tby lists.gnu.org with esmtp (Exim 4.90
> 
> This was fixed in Exim, it looks like,
> 
>    https://bugs.exim.org/show_bug.cgi?id=2454
> 
> but I wanted to prod you about upgrading because we can't turn that 
> feature off and you're probably dropping a significant chunk of mail due 
> to it.
> 
> 

Thanks for the heads up. That is a very new exim, I'm going to look into
a way to avoid this through configuration rather than upgrade.

-- 
Ian Kelling | Senior Systems Administrator, Free Software Foundation
GPG Key: B125 F60B 7B28 7FF6 A2B7  DF8F 170A F0E2 9542 95DF
https://fsf.org | https://gnu.org