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Forum Team (Retired) Jen_A
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Message 41 of 97
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Re: Sending emails is OK during the day but stops at night?

Hi andymanu & coenoby,

Was Outlook running on the night of the 5th/6th?

Here is a slice of action from 06/12/2018:

Successful auth attempts only(enough to trigger a VM320 error):
00:00:01.107 - 00:01:18.087 

Auth rejected/VM320:
00:01:18.195 - 01:00:00.279

Successful auth attempts only(enough to trigger a VM320 error):
01:00:06.336 - 01:00:55.972

Auth rejected/VM320:
01:00:56.083 -  01:59:58.290

Successful auth attempts only(enough to trigger a VM320 error):
02:00:05.369 - 02:01:09.116

Auth rejected/VM320:
02:01:09.808 - 02:59:56.305

Successful auth attempts only(enough to trigger a VM320 error):
03:00:01.501 - 03:00:07.093

Auth rejected/VM320:
03:00:07.205 - 03:59:56.030

Successful auth attempts only(enough to trigger a VM320 error):
04:00:01.183 - 04:00:06.567

Auth rejected/VM320:
04:00:06.670 - 04:59:57.010

Successful auth attempts only(enough to trigger a VM320 error):
05:00:02.195 - 05:00:05.093

Regards,


Jen
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coenoby
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Message 42 of 97
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Re: Sending emails is OK during the day but stops at night?


@Jen_A wrote:

Hi andymanu & coenoby,

Was Outlook running on the night of the 5th/6th?

Here is a slice of action from 06/12/2018:


Thank you very much for taking the time to provide that information Jen. Fascinating to see if it turns out that Outlook was definitely not running.

It seems as if there is something scheduled to generate those authorisation attempts over night but is not running during the day. If it was then surely andymanu would be having problems sending emails throughout the day?

Coenoby

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Forum Team (Retired) Jen_A
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Message 43 of 97
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Re: Sending emails is OK during the day but stops at night?

Checking todays' data the whole process began again just after midnight, at 00:26:44.195 and ended at 05:00:06.358. No emails sent at all so I'm assuming that Outlook is still shutdown. We'll wait to see what input Steve has.

If Outlook is off the list of possible suspects then we'll need to narrow down the connected devices and take it from there. Intriguing...

 


Jen
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Superuser
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Message 44 of 97
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Re: Sending emails is OK during the day but stops at night?

I find this intriguing to say the least.

I'm still leaning towards malware here, as with most mail clients I know - there's no reason to authenticate unless you're actually sending a mail.

Also bear in mind that while I don't know the Auth attempt hourly limits for onnet - it's likely to be higher than offnet, or at the very least equal.  Those limits are likely set high enough as to not impact normal email usage, yet we see them exhausted in around a minute.  Then shortly after  the hourly timeout expires the whole process begins again.

My first thought would have been a brute force attack - HOWEVER - these are all successful authentications - whereas a brute force attack is normally an attempt to determine a valid username/password thus you'd normally expect to see a number of failed attempts using different passwords (and normally such attempts would be blocked fairly quickly - I have fail2ban on my mail server and I don't doubt Virgin Media along with most other ESP's are running something similar.

My other thought would be an attempted DOS attack, certainly if I wanted to knock a server offline, flooding it with repeated auth connections might be one way to go about it.  I should stress that I'm not accusing @andymanu here, but I'm merely ruminating on why we might see repeated successful auth attempts with no email actually being delivered.

On the other hand it COULD be a buggy email program, but I find that unlikely.  Most email programs I know won't connect unless there are mail/s in the outbox, and once it's authenticated successfully those mails are sent (indeed the OP has advised that this actually happened with his mail).

Very odd if I may say so.

Tim

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coenoby
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Message 45 of 97
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Re: Sending emails is OK during the day but stops at night?


@ravenstar68 wrote:

I find this intriguing to say the least.

I should stress that I'm not accusing @andymanu here, but I'm merely ruminating on why we might see repeated successful auth attempts with no email actually being delivered.

For me it's probably the most interesting post I have been involved with on this forum.

I just hope that andymanu sticks with us until the answer is found.

Having got so far it would be so frustrating not to find out what is going on. Smiley Sad

Coenoby

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Superuser
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Message 46 of 97
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Re: Sending emails is OK during the day but stops at night?

This issue is beginning to sound like “Modern Authentication goes bananas”. So, here’s a theory. 

MA is the Microsoft term for what I would describe as a client/server implementation of access control which is firmly aimed at corporate environments where the user desktop interacts with Exchange/Office 365 for authentication. It was first implemented in Outlook 2013 and 2016. 

MA is installed by default in Outlook 2016, so all the code must be present in the standard product regardless of it being on an individual private user PC or corporate desktop. 

So, if there is a bug or a corruption in stored data in Outlook 2016 such that it thinks it is in a MA environment, then it may repeatedly send Auth requests when (erroneously) triggered. This might explain why there is no message delivery attempt - just Auth requests. 

And then there are admin controls to govern the timeslots when Outlook may or may not do things. Like send mail between midnight and 05:00 – so if it attempts to Authenticate at midnight……..and loops until 05:00, it could be a data setting corruption. 

The above scenario requires a number of things to be wrong - a corrupt data store flag controlling the time on/off controls and/or code bugs in the Outlook application . But stranger things have happened before now. 

It may be that most corporates will have moved on to a 365 setup leaving a reduced pool of individual users using Basis Authentication only in Outlook 2016. So, fewer bug reports for 2016 itself. 

Some background reading -

https://docs.microsoft.com/en-us/office365/enterprise/modern-auth-for-office-2013-and-2016

https://www.peters.com/modern-authentication-adal/

https://www.peters.com/modern-authentication-part-2/ 

So – anyone with relevant MA experience out there?

Post a bug report with Microsoft Support?

Re-install Outlook?

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Superuser
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Message 47 of 97
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Re: Sending emails is OK during the day but stops at night?

I love reading Microsoft Docs as some of them have phrases that make absolutely zero sense.

Take this one.

https://docs.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/outlook-for-ios-and-...

It talks about providing your SMTP username and password.

HOWEVER

MA is a feature of Microsoft Exchange servers mainly Office 365 but also "On premises accounts leveraging hybrid Modern Authentication."

But in the article they show the path to manually set up the account when authentication fails, and this is as an Exchange account.

One important thing about Exchange accounts is that they DON'T USE IMAP or SMTP - (While Exchange servers do support these protocols, Exchange accounts actually use MAPI for sending and receiving mail - the Exchange Server then sends outbound mail onwards using SMTP).

So I think talk of MA is a red herring here.

Tim

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Message 48 of 97
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Re: Sending emails is OK during the day but stops at night?

An additional thought regarding MA

For an SMTP client to use a particular AUTH type - the server MUST announce it as part of the capabilities.

For example here's Microsoft's SMTP server

250 SMTPUTF8
ehlo desktop
250-CWLP265CA0212.outlook.office365.com Hello [80.195.xxx.xxx]
250-SIZE 157286400
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-AUTH LOGIN XOAUTH2
250-8BITMIME
250-BINARYMIME
250-CHUNKING
250 SMTPUTF8

Note that the two AUTH mechanisms allowed are Login (which sends the Base64 Encoded username and password separately), or OAuth (which is a SASL token based login mechanism)

Here on the other hand is Virgin Media's

220 know-smtprelay-4-imp cmsmtp ESMTP server ready
ehlo desktop
250-know-smtprelay-4-imp hello [80.195.xxx.xxx], pleased to meet you
250-HELP
250-AUTH LOGIN PLAIN
250-SIZE 52000000
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-8BITMIME
250 OK

Here we see the only AUTH types allowed are LOGIN or PLAIN (which sends the base64 encoded username and password together)

So Outlook would not attempt to use any other mechanisms.  This also rules out MA gone bananas.

Tim

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andymanu
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Message 49 of 97
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Re: Sending emails is OK during the day but stops at night?

Thank you to Coenoby, Tim and everyone else who is trying to help me.

I have not had any problems with sending emails; hence my relatively long absence of posting about the issue.
That is, until this morning when I tried to send an email at around 12.15 am. It is still stuck in the out box. I am getting the same messages i.e. "enter your user name and password for the following server: smpt.virginmedia.com"
I have been working from home today, so have had Outlook open for most of the day, but I don't think that is connected? I have hardly used Outlook today and the auto send and receive is set to 60 mins.
I have uninstalled and re-installed Office 16 to no avail.
I have a activated MS Office Professional 2016 Version 1811 (Build 11029.20108 Click to Run) and up to date.

Any ideas/solutions are gratefully considered and attempted

Steve

(As a matter of perhaps slight interest but off topic, I am having even bigger problems at my small company where it is an exchange account and the exchange cannot find my mailbox and has put everything into a temp mailbox where I cannot send and receive anything at all; its like it is frozen in time on a certain date. MS cannot help and neither can our IT providers. I must be jinxed!)
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coenoby
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Message 50 of 97
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Re: Sending emails is OK during the day but stops at night?


@andymanu wrote:
 tried to send an email at around 12.15 am. It is still stuck in the out box. I am getting the same messages i.e. "enter your user name and password for the following server: smpt.virginmedia.com"

Did that email eventually get sent after 5.00am as per the pattern that was seen with your emails a while ago?

Coenoby

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