n4l bulk relay

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Craig Knights

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Mar 10, 2022, 5:56:01 PM3/10/22
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Hi all, we seem to being having trouble this morning doing emails out of Kamar through the n4l bulk relay: 

bulk-relay.n4l.co.nz


anyone else having trouble?

cheers,
Craig

Nick Steenson

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Mar 10, 2022, 5:57:37 PM3/10/22
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Have you checked the KAMAR messaging log? Last time I suspected the N4L relay the KAMAR server was just backed up with ~2000 pending outgoing emails that it was attaching files to and sending individually (as they had individual content).

Nick

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Simon Wright

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Mar 10, 2022, 5:58:10 PM3/10/22
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don't think there is a bulk relay anymore? isn't it just relay.n4l...


Regards,

Simon Wright


On Fri, 11 Mar 2022 at 11:56, Craig Knights <craig....@gmail.com> wrote:
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Craig Knights

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Mar 10, 2022, 6:00:08 PM3/10/22
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hmmm, dunno Simon.

I'm getting this error

2022/03/11 09:41:52    Info   Messaging             Update Status: Sending Messages: 200 / 529

2022/03/11 09:41:57    WARN   Messaging             Last send had an error. (ERROR: 400 - Server has closed the connection------2022-03-11 09:41:57    Sending Email2022-03-11 09:41:57    ERROR: Receive Data - Connection Closed2022-03-11 09:41:57    Send Error!2022-03-11 09:41:57    ERROR: Receive Data - Connection Closed2022-03-11 09:41:57    Disonnect Remote Server Failed2022-03-11 09:41:57    Disconnecting2022-03-11 09:41:57    Disconnected)

2022/03/11 09:41:57    Info   Messaging             Reconnect in 2 seconds. Attempt: 2

2022/03/11 09:41:59    Info   Messaging             Connected to bulk-relay.n4l.co.nz. Attempt: 2


Craig Knights

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Mar 10, 2022, 6:01:52 PM3/10/22
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it's still there in their online docs written 2021

Craig

Nick Steenson

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Mar 10, 2022, 6:03:37 PM3/10/22
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I have that error every now and then, but the subsequent email (a retry) seems to work fine. Then there's a whole lot of success, then that error again. Only seems to happen on big/long lists of emails though, and it looks like you've queued 529?

Nick

Ben Green

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Mar 10, 2022, 6:05:16 PM3/10/22
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Bulk-relay looks to be working fine for us.
Headers show received by relay.mimecast.com these days (as opposed to anything N4L).

- Ben.

From: 'Nick Steenson' via Techies for schools <techies-f...@googlegroups.com>
Sent: Friday, 11 March 2022 12:03 pm
To: techies-f...@googlegroups.com <techies-f...@googlegroups.com>
Subject: Re: [techies-for-schools] n4l bulk relay
 
Christchurch Boys' High School
phone: +64 3 348 5003
address: 71 Straven Road, Riccarton, Christchurch 8014
postal: PO Box 8157, Riccarton, Christchurch 8440
web: www.cbhs.school.nz

Clayton Hubbard

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Mar 10, 2022, 6:30:50 PM3/10/22
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Hi Nick,

I would suggest you fire a ticket to sup...@n4l.co.nz and the guys can check mimecast logs to see what is happening here.

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Clayton Hubbard
Enterprise Architect
0220430155

Nick Steenson

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Mar 10, 2022, 6:35:37 PM3/10/22
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Hi,

Can do, though it has no functional downside, it all works fine for me (I was just letting Craig know that error isn't unique, and likely doesn't have a real effect/cost)

Nick

Craig Knights

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Mar 10, 2022, 6:38:08 PM3/10/22
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Currently I'm just going to see what happens...

Someone has sent 2MB of screenshots to 1057 recipients, and it's currently up to message 664.  They say, "but it's done it fine before..."

I'm not going to do anything drastic and break it as we do have some important stuff going out at 4pm.

Question is, if someone does a dumb thing like this, and I then use the send test email from the server setup page, does it get queued in Kamar??  So I won't get that until it finishes the 1057 emails?







Nick Steenson

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Mar 10, 2022, 6:44:48 PM3/10/22
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Correct. Test emails get added to the end of the queue too.

I get a call about it about once a fortnight.

Nick

Kent

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Mar 10, 2022, 7:15:18 PM3/10/22
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Hi Craig,

N4L used to use a local, Spark provided email relay. Since late last year they have moved their mail sending to use services hosted by Mimecast.

Doing a dig, both bulk-relay.n4l.co.nz and relay.co.nz are pointing to the same location now - so they are one in the same for all purposes.
> bulk-relay.n4l.co.nz. 300 IN CNAME au-smtp-outbound-2.mimecast.com.
> relay.n4l.co.nz. 154 IN CNAME au-smtp-outbound-1.mimecast.com.



There are a couple of things as a result of this change:

1) It's an overseas based mail relay service. We have observed sending is now noticeably slower (ping = 28ms) than before when N4L was using the Spark relay (ping = 3ms) - especially when your school is sending attachments.

2) We use a single connection to send multiple emails as this is a lot quicker than connecting, send, disconnect (repeat for each email). However, like other services, Comcast impose a maximum of 200 emails we can send per connection. The error you see in the log is once we reach this limit.


Because each service impose different limits (and even return different errors when the limit is reached) - we have a generic check, disconnect and then reconnect.
Some services impose multiple limited. eg. smtp.google.com imposes both per minute and per connection limits, so we actually have to slow down sending when we hit these limits.
What you are seeing in the logs is expected bahaviour.


KAMAR is just like any other mail client (eg. Outlook). If you generate 3000 separate email and them pressed Send all at once, your mail client is going to sit there and chug away sending each one in turn. If the mail server is local / same network it's going to send a lot quicker than if your mail server is based outside the network / overseas.


Solutions:
• If you host KAMAR yourself, you could install a local mail server. Have KAMAR send to that and then the mail server relay via relay.n4l.co.nz.
• Investigate if there is a NZ based mail relay service that you can use with less overhead than mimecast.
• Use our mail service school.kiwi.


Note: We are early stages of investigating how we can split this task into multiple threads within KAMAR but still early planning stages. At minimum we want to split each batch into its own thread, so someone sending an attachment to every caregiver of the whole school doesn't hold up the next person who tries to send an email - but even with this approach we will strike issues with googles mail servers.


Cheers
Kent



Notes:
• ping testing from Tauranga
• 3ms spark ping time was from testing we did a year+ ago prior to the change to Mimecast.
• I couldn't ping the mimecast servers themselves, but using traceroute I identified the last pingable device in the route as 124.47.131.210 and pinged that.
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Simon Wright

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Mar 10, 2022, 7:17:27 PM3/10/22
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Same, someone will send an email out to every parent and student, ~2500+ emails, then after an hour wonder why no one has received it and send again.
Also try to encourage not sending attachments via kamar but rather upload to google drive and create a shared link.


Regards,

Simon Wright


Craig Knights

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Mar 10, 2022, 8:01:57 PM3/10/22
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thanks Kent, very helpful.

Craig

Jonathan Churton

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Mar 10, 2022, 9:44:28 PM3/10/22
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Whip up an internal mail-relay server. hMailServer has been good to us. No problems ever since then.

Staff said it was a night and day difference. Kamar -> Internal (Buffer) -> N4L/Mimecast

Cheers.



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Craig Knights

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Mar 10, 2022, 10:31:23 PM3/10/22
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We already have one for the copiers.  

So the hmail will hose them out through the relay faster too?

Jonathan Churton

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Mar 10, 2022, 11:07:30 PM3/10/22
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If you're talking about blasting kamar emails through hMail/Relay? yes.

hMail is async both inbound and outbound, so it's spinning up multiple SMTP connections to mimecast.

Craig Knights

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Mar 10, 2022, 11:09:50 PM3/10/22
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OK. Awesome. Thanks.  I'll experiment next week.

Andrew Godfrey

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Mar 10, 2022, 11:16:26 PM3/10/22
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We use Mercury32 with three instances on the same server on different ports so the large kamar jobs don't hold up the voicemail, copy to email, etc.

It was important to get them out of kamar quickly so the PC would be useable again  in the day when the the email got sent out from the client rather than the server.


On Fri, 11 Mar 2022, 3:44 pm Jonathan Churton, <jonathan...@whs.school.nz> wrote:
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