Exchange 2016: What if disable all HealthMailbox mailboxes?

The idea of the post is issue that we faced recently. Sometimes Outlook freezed for a while with warning message.

At the same time SCOM started to warn about issues with Application Pool of one Exchange server. This issues should be linked, but how? 

Exchange server registered warnings 5011 in System Event Log:

Exchange 2016 - High CPU utilization by Microsoft Exchange Replication Service (MSExchangeMailboxReplication)

I had faced with that issue on my work and with Microsoft support we found the core issue and solved it.

Unfortunately, I haven't been able to reproduce this issue in my home lab, but I'll try to describe all main points.

Procmon was showing that "MSExchangeMailboxReplication.exe" process always (hundreds of times per second) try to open (RegOpenKey) "HKLM\SOFTWARE\Microsoft\ExchangeServer\v15\ActiveManager\TestOverride" reg key.

Adding the "TestOverride" registry key doesn't solve the problem. The process started to searching other keys.

Exchange 2016 - Limits and impact of Transport Rules (Mailflow Rules)

Sometimes, to solve complex problems, you have to use transport rules. But what are the limitations of this functionality?
I decided to cover 2 questions:

Part 1. How big may the transport rule be?

All transport rules are stored in the "CN=TransportVersioned,CN=Rules,CN=Transport Settings,CN=<Organization>,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=<domain>,DC=<domain>" container. The rule itself is a XML that is stored in the "msExchTransportRuleXml" attribute.

Exchange 2016: Issue of breaking email address in angle brackets

Recently noticed the unusual behavior (an issue) of Microsoft Exchange 2016 when displaying email addresses.
If in the body of an email (Content/Header section) specify an email address (From, To or Cc headers) twice, where the second time is in angle brackets, the address will be broken. The part of the address after the first character @ moves to the address in brackets, thereby preventing the possibility of an answer to this email.

I assume that the function that should extract the correct email addresses from the headers does not work correctly.

Several tests

Original email address (that used while sending)	The final email address (OWA, Outlook)
administrator@test.local <administrator@test.local>	"administrator@" <test.local administrator@test.local>
administrator@_ <administrator@test.local>	administrator@ <_ administrator@test.local>
administrator@domain<administrator@test.local>	administrator@ <domainadministrator@test.local>
administrator@><administrator@test.local>	<administrator@>
<administrator@><administrator@test.local>	<administrator@>
<@administrator@><administrator@test.local>	<@administrator@><administrator@test.local>
administrator@<administrator@test.local>	<administrator@>
<script>@><administrator@test.local>	<script>
administrator@test.local@ <administrator@test.local>	"administrator@" <test.local@administrator@test.local>

Outlook 2013/2016: Types of connections to Microsoft Exchange

In this post, I would like to make out the types of Microsoft Outlook 2013/2016 connections to the Microsoft Exchange Server 2016, depending on the type of mailbox (personal, archive, shared or Public Folders).
There are 2 main types of connections: cached and online. The online mode is simple, but the cache mode is more complex. To learrn more what is Cached Mode go to TechNet.

Exchange 2016: setup tried to install wrong CU version

Recently faced an interesting feature on the start at installation of Cumulative Update.

When starting CU setup from the command line, the installation of the current version can start.

An example:
[PS] C:\Windows\system32>cd d:\
[PS] D:\>setup /PrepareSchema
Microsoft Exchange Server 2016 Cumulative Update 6 Unattended Setup

Exchange 2016: How to force it use UTF-8 encoding

In order to minimize the number of possible problems with message encode (e.g. "?" instead of Cyrillic symbols), I recommend to set up an unified universal encoding in the Exchange - UTF-8.

Quotation from the TechNet article regarding choosing encoding for outgoing emails:

"Exchange uses the order of precedence as described in the following list to determine the message encoding options for outgoing messages sent to recipients outside the Exchange organization"

1. Mail user or mail contact settings

There are no specific attributes to determine encoding for MailContact and MailUser.

Exchange 2016: How many attachments may be in the email?

Have you ever wondered how many files you may attach to an email?
For Microsoft Exchange 2016 (CU6) is 249 (250 MIME parts). And it is an unchangeable parameter. Not so much, isn't it?

MaxBodyPartsTotal
This limit specifies the maximum number of message parts that can be used in a MIME multipart message. The value is 250.
https://technet.microsoft.com/en-us/library/bb397226(v=exchg.150).aspx

In the RFCs I can't find any mention of maximum number of MIME parts or attachments. Also I found information that in Gmail there is no limitation to number of files attached, only message size (300 files was delivered perfectly). Feel free to correct me if I'm wrong.

Exchange 2016: How to move system mailboxes

Exchange 2016 has 5 types of system mailboxes: Discovery Search (1 mbx), Arbitration (6 mbx), AuditLog (1 mbx), Public Folder (not created by default) and Monitoring (the number depends on the number of databases). All of them are necessary for full-fledged Exchange's work.

You can't delete the first mailbox database (or another one) until all system mailboxes migrate to a new database.

Exchange 2016: Do I need update AD schema?

Not each Cumulative Update of Microsoft Exchange 2016 contains updates to the AD schema. I decided to present it in the simple table.
Hope it will useful to someone.

FROM

RTM

CU1

CU2

CU3

CU4

CU5

CU6

CU7

CU8

CU9

CU10

CU11

CU12

CU13

CU14

TO

RTM

CU1

Yes

CU2

Yes

Yes

CU3

Yes

Yes

Yes

CU4

Yes

Yes

Yes

No

CU5

Yes

Yes

Yes

No

No

CU6*

Yes

Yes

Yes

Yes*

Yes*

Yes*

CU7

Yes

Yes

Yes

Yes

Yes

Yes

Yes

CU8

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

CU9

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

CU10

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

CU11

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

CU12

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

CU13

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

No

CU14

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

No

No

* Increased only the version number. Officially CU6 does not contain AD Schema update.

I am finished updating this article because Microsoft built perfect tool to help with Exchange updates - Exchange Update Wizard.

Exchange 2016 on Windows Server 2012 R2 Core

I know that Microsoft doesn’t support Exchange 2016 on Windows Server Core or Nano Server. But I decided to find out is it possible or not.

During install Exchange 2016 CU3 on Windows Server 2012 R2 Core (Standard Edition without "Server-Gui-Shell" and "Server-Gui-Mgmt-Infra" features) with checked "Automatically install Windows Server roles and features that are required to install Exchange Server" wizard installs GUI by self.

Exchange 2016 at home

Is it possible to install, configure, and use Microsoft Exchange Server at home with gray IP? Yes, of course. What for? Just for fun.

Scheme

How I did it.

Exchange 2013 - 2016. Email in Draft: You don't have permission to perform this action

Today I faced with interesting behavior of Exchange 2016. After the initial configuration I tried to send the email and got the error "You don't have permission to perform this action".

Microsoft Exchange 2016 and OwaVersion:Exchange2013

During the study of Exchange 2016 RTM I noticed one thing - "OwaVersion" of OWA Virtual Directory is "Exchange2013". CU1 - CU14 still no changed it.

[PS] C:\Windows\system32>Get-ExchangeServer | fl AdminDisplayVersion
AdminDisplayVersion : Version 15.1 (Build 466.34)

[PS] C:\Windows\system32>Get-OwaVirtualDirectory | fl OWAVersion
OwaVersion : Exchange2013