<div><div dir="auto">I forgot to mention: the timestamps on your problem emails happen before they started work on the ironports. So I don't think it's related. </div><br><div class="gmail_quote"><div>On Thu, Aug 17, 2017 at 10:21 AM Gilbert E. Detillieux <<a href="mailto:gedetil@cs.umanitoba.ca">gedetil@cs.umanitoba.ca</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Trevor,<br>
<br>
The problem may be at your end. (Have you changed anything there<br>
recently?) My reply to your address bounced when sent from my sendmail<br>
server, which hasn't changed in a long time. Here's what I got in the<br>
bounce message...<br>
<br>
----- The following addresses had permanent fatal errors -----<br>
<<a href="mailto:trevor@tecnopolis.ca" target="_blank">trevor@tecnopolis.ca</a>><br>
(reason: 550 <<a href="mailto:trevor@tecnopolis.ca" target="_blank">trevor@tecnopolis.ca</a>>... 451 4.7.1 Greylisting in<br>
action, please come back later)<br>
<br>
----- Transcript of session follows -----<br>
... while talking to <a href="http://tecnopolis.ca" rel="noreferrer" target="_blank">tecnopolis.ca</a>.:<br>
>>> DATA<br>
<<< 550 <<a href="mailto:trevor@tecnopolis.ca" target="_blank">trevor@tecnopolis.ca</a>>... 451 4.7.1 Greylisting in action,<br>
please come back later<br>
550 5.1.1 <<a href="mailto:trevor@tecnopolis.ca" target="_blank">trevor@tecnopolis.ca</a>>... User unknown<br>
<<< 503 5.0.0 Need RCPT (recipient)<br>
<br>
--v7HEwiKb114371.1502981924/<a href="http://copper.cs.umanitoba.ca" rel="noreferrer" target="_blank">copper.cs.umanitoba.ca</a><br>
Content-Type: message/delivery-status<br>
<br>
Reporting-MTA: dns; <a href="http://copper.cs.umanitoba.ca" rel="noreferrer" target="_blank">copper.cs.umanitoba.ca</a><br>
Received-From-MTA: DNS; <a href="http://lockwood3.cs.umanitoba.ca" rel="noreferrer" target="_blank">lockwood3.cs.umanitoba.ca</a><br>
Arrival-Date: Thu, 17 Aug 2017 09:58:37 -0500<br>
<br>
Final-Recipient: RFC822; <a href="mailto:trevor@tecnopolis.ca" target="_blank">trevor@tecnopolis.ca</a><br>
Action: failed<br>
Status: 5.1.1<br>
Remote-MTA: DNS; <a href="http://tecnopolis.ca" rel="noreferrer" target="_blank">tecnopolis.ca</a><br>
Diagnostic-Code: SMTP; 550 <<a href="mailto:trevor@tecnopolis.ca" target="_blank">trevor@tecnopolis.ca</a>>... 451 4.7.1<br>
Greylisting in action, please come back later<br>
Last-Attempt-Date: Thu, 17 Aug 2017 09:58:44 -0500<br>
<br>
On 17/08/2017 3:22 AM, Trevor Cordes wrote:<br>
> I just started getting some weirdness with some email sent to my mail<br>
> servers. Greylisting "come back later" (451) messages are being<br>
> interpreted (it appears) by remote MTAs as a 5xx level error, meaning they<br>
> immediately abort send attempts and bounce the email! I have never seen<br>
> this before.<br>
><br>
> I've seen it from two separate remote MTAs so far, but from reports I'm<br>
> getting in, it's happening on more.<br>
><br>
> Here's what I get from <a href="http://umce3cip03.ad.umanitoba.ca" rel="noreferrer" target="_blank">umce3cip03.ad.umanitoba.ca</a>:<br>
><br>
> Remote Server returned '554 5.0.0 <[50.71.247.87] #5.0.0 smtp; 5.1.0 -<br>
> Unknown address error 550-'<<a href="mailto:foobar@tecnopolis.ca" target="_blank">foobar@tecnopolis.ca</a>>... 451 4.7.1 Greylisting<br>
> in action, please come back later' (delivery attempts: 0)>'<br>
><br>
> On my server sendmail log I see:<br>
><br>
> Aug 16 08:43:15 pog sendmail[14379]: v7GDhFav014379: Milter:<br>
> to=<<a href="mailto:foobar@tecnopolis.ca" target="_blank">foobar@tecnopolis.ca</a>>, reject=451 4.7.1 Greylisting in action, please<br>
> come back later<br>
><br>
> So <a href="http://umce3cip03.ad.umanitoba.ca" rel="noreferrer" target="_blank">umce3cip03.ad.umanitoba.ca</a> appears to be taking my 451 and turning it<br>
> into a 500/554/510 permanent error.<br>
><br>
> I also see this from yahoomail, but that's a different situation because<br>
> yahoo is always considered "broken mta" in milter-greylist and we must<br>
> whitelist all of their servers... but, the usual/previous symptom was<br>
> yahoo would keep retrying as normal, just with a different IP each time,<br>
> thus never passing greylisting. And now yahoo is doing the same thing as<br>
> <a href="http://umce3cip03.ad.umanitoba.ca" rel="noreferrer" target="_blank">umce3cip03.ad.umanitoba.ca</a> above (when I haven't yet whitelisted the<br>
> particular IP that day, grrr):<br>
><br>
> Sorry, we were unable to deliver your message to the following address.<br>
> <<a href="mailto:foo@tecnopolis.ca" target="_blank">foo@tecnopolis.ca</a>>:<br>
> 550: <<a href="mailto:foo@tecnopolis.ca" target="_blank">foo@tecnopolis.ca</a>>... 451 4.7.1 Greylisting in action, please<br>
> come back later<br>
...<br>
<br>
--<br>
Manitoba UNIX User Group E-mail: <<a href="mailto:gedetil@muug.ca" target="_blank">gedetil@muug.ca</a>><br>
c/o Gilbert E. Detillieux Web: <a href="http://muug.ca/" rel="noreferrer" target="_blank">http://muug.ca/</a><br>
University of Manitoba Phone: (204)474-8161<br>
Winnipeg MB CANADA R3T 2N2 Fax: (204)474-7609<br>
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</blockquote></div></div><div dir="ltr">-- <br></div><div data-smartmail="gmail_signature">Micah Garlich-Miller <<a href="mailto:micahgarlichmiller@gmail.com" target="_blank">micahgarlichmiller@gmail.com</a>><br></div>