[Mailman-Users] Erratic mail delivery times

[Peter Shute]

Thanks for taking the time to reply to those points. Since my discovery and fixing of the diskspace problem that was causing Exchange to apply what it calls back pressure to incoming mail, the delays have continued. The disk space problem had only been adding to the problem, not causing it.

I've now enabled protocol logging on our Exchange server, a new world for me. I can see several possibly relevant events in yesterday's logs that look like this:
2014-07-17T07:02:03.914Z,NUWVICMS2\Default NUWVICMS2,08D145520008BC68,24,192.168.0.36:25,192.64.112.70:38732,>,550 5.7.1 Requested action not taken: message refused,

192.64.112.70 is the list's mail server, and I can see entries where mail has been delivered successfully from that address.

Googling that message found a few people blaming it on Symantec antispam, which we use here at work.

As a test, I subscribed myself a second time to the same list with a gmail address. I sent a test message to the list, and it came through to the gmail address within a minute or two, but took 66 minutes to reach my work address.

Then I subscribed a thrid time with an outlook.com address and sent another test message. Again it arrived in the gmail mailbox within a couple of minutes. It arrived in the outlook.com and my work mailboxes around the same time, 12 minutes later.

I believe outlook.com also used Symantec antispam, so this seems to be the common factor. It makes sense that this might suddenly start happening, coinciding with an antispam signature update.

But if the antispam software is refusing the messages, how do they eventually get through?

Peter Shute

> -----Original Message-----
> From: Mailman-Users 
> [mailto:mailman-users-bounces+pshute=nuw.org.au at python.org] 
> On Behalf Of Stephen J. Turnbull
> Sent: Tuesday, 15 July 2014 4:30 PM
> To: Barry S. Finkel
> Cc: mailman-users at python.org
> Subject: Re: [Mailman-Users] Erratic mail delivery times
> 
> Barry S. Finkel writes:
>  > On 7/14/2014 8:43 PM, Peter Shute wrote:
> 
>  > > Would grey listing show up in the headers? We haven't 
> installed  > > grey listing here, but who know what our anti 
> spam does. If it's  > > using it then it certainly isn't 
> using it consistently. I can't  > > see anything in the 
> Exchange Message Tracking logs that shows  > > anything 
> unusual as they come in. They simply arrive late.
> 
> It might, depending on the receiving software.  My system shows this:
> 
> X-Greylist: IP, sender and recipient auto-whitelisted, not 
> delayed by milter-greylist-1.6 (mx.example.org [10.0.0.1]); 
> Mon, 14 Jul 2014 21:57:46 -0400 (EDT)
> 
>  > > These are the top two headers from a delayed message. 
> Does this  > > tell me anything other than it was received by 
> the server  > > upstream of mine 21 minutes before it was 
> received by mine?
> 
> Not that I can see.
> 
>  > > If so then the delay could be before that upstream 
> server sent it  > > on, or while it waited for my server to accept it.
> 
> Yes.
> 
>  > > If it tried several times, would that be shown in the headers?
> 
> Normally, no.
> 
>  > The server26 machine accepted the mail from localhost at 18:50:48 .
>  > The NUWVICMS2 machine accepted the mail from server26 at 
> 09:11:01  > The time difference is 9:12 + 11:01 = 20:12.  
> Twenty minutes seems  > a long time for greylisting.
> 
> Why?  My host will continue to refuse mail for 15 minutes 
> before autowhitelisting, but most mail gets delayed for 2-4 
> hours depending on the retry cycle of the sending machine 
> (the host doesn't get a lot of mail from most sites).
> 
> 
>  > You would have to look at the mail logs from the NUWVICMS2 
> machine  > to see what it was doing from 08:50 until 09:11 
> (GMT+1000) to know  > why the mail was delayed.  Also, the 
> logs on the server16 machine  > would probably tell if 
> server26 tried an earlier connection to the  > NUWVICMS2 machine.
> 
> This should also appear in the NUWVICMS2 machine logs if it 
> was greylisting.
> 
> Steve
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