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From: Stanley Lieber <sl@stanleylieber.com>
To: 9front@9front.org
Subject: Re: [9front] transient dns errors cause smtp failure
Date: Sun, 07 Feb 2021 11:53:45 -0500	[thread overview]
Message-ID: <477917F0-25D1-481A-8CF7-F371554DF2E8@stanleylieber.com> (raw)
In-Reply-To: <1B74CAEE535895AEA8BD0EFB600EF335@hog>

On February 7, 2021 8:56:39 AM EST, kvik@a-b.xyz wrote:
>I think I found a reason for DNS failing on known good domains.
>
>/sys/src/cmd/ndb/dns.h:156,157
>	/* tune; was 60*1000; keep it short */
>	Maxreqtm=	8*1000,	/* max. ms to process a request */
>
>So, 8 seconds is how much the resolver will bother with a request it
>has been handed, before dropping it on the floor with little
>explanation.
>
>It seems quite possible that this is too short a timeout on a machine
>during a spam queue run, which predictably stresses the compute and
>network resources.
>
>In turn, negative response caching might explain why a particular
>unlucky domain would basically stop receiveing any mail for a while.
>
>I'm dying to know if bumping this limit would clear up the queue of
>such DNS errors.
>
>

i cranked Maxreqtm to 30*1000 and it's already making a huge difference cleaning out the queue. we'll see how it plays out.

thanks!

sl

       reply	other threads:[~2021-02-07 16:55 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1B74CAEE535895AEA8BD0EFB600EF335@hog>
2021-02-07 16:53 ` Stanley Lieber [this message]
2021-02-09 15:58   ` kvik
2021-02-09 16:41     ` Stanley Lieber
2021-02-10 15:24 ` Stanley Lieber
2021-02-10 16:30   ` ori
2021-02-17 23:14 ` sl
2021-02-17 23:55   ` ori
2021-02-19  6:54   ` cinap_lenrek
2021-02-06  1:59 Stanley Lieber
2021-02-06  6:17 ` ori
2021-02-06  7:19   ` Stanley Lieber
2021-02-06 10:24     ` hiro
2021-02-06 15:03 ` sirjofri
2021-02-06 16:41   ` sirjofri

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