From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id 6F717138350 for ; Mon, 6 Apr 2020 13:15:36 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 5B695E0D38; Mon, 6 Apr 2020 13:15:31 +0000 (UTC) Received: from smtp.gentoo.org (dev.gentoo.org [IPv6:2001:470:ea4a:1:5054:ff:fec7:86e4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id E6365E0C8D for ; Mon, 6 Apr 2020 13:15:30 +0000 (UTC) Received: from [192.168.1.100] (c-98-218-46-55.hsd1.md.comcast.net [98.218.46.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: mjo) by smtp.gentoo.org (Postfix) with ESMTPSA id DF9F834F085 for ; Mon, 6 Apr 2020 13:15:29 +0000 (UTC) Subject: Re: [gentoo-user] Alternate Incoming Mail Server To: gentoo-user@lists.gentoo.org References: <20200406123504.fkcuaiiahsemympv@ad-gentoo-main> <20200406130812.n4zgquadlgkggi7u@ad-gentoo-main> From: Michael Orlitzky Message-ID: <8495c9e0-269a-eb83-48d4-15af57adb5ca@gentoo.org> Date: Mon, 6 Apr 2020 09:15:27 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org X-Auto-Response-Suppress: DR, RN, NRN, OOF, AutoReply MIME-Version: 1.0 In-Reply-To: <20200406130812.n4zgquadlgkggi7u@ad-gentoo-main> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Archives-Salt: 927d61bc-4507-4226-b920-7478071e4f2f X-Archives-Hash: e38208f50b63446349e32793dd2a8b0b On 4/6/20 9:08 AM, Ashley Dixon wrote: > On Mon, Apr 06, 2020 at 08:41:20AM -0400, Michael Orlitzky wrote: >> There's no need, the SMTP specification says that senders must retry >> every message, and should continue retrying for at least 4 or 5 days: >> >> https://tools.ietf.org/html/rfc5321#section-4.5.4 > > That's a relief, cheers. > > Excuse the skeptic within me, but is it safe to assume this specification is > strictly followed by all mail-transfer agents ? I.e., are there any common > M.T.A.s which do not continue trying to send for a few days ? > All real MTAs follow the specification. A few email service providers (think SendGrid, MailChimp, etc.) allow their users to configure how many retries will be made, and every once in a while you have users who set it to zero because they see a button and can't resist pushing it. But those emails are never anything critical to begin with, in my experience, and it's a rare problem nonetheless.