Use Local Group Policy editor by running gpedit.msc and modifying the policy.

Computer Configuration -> Administrative Templates -> Network -> DNS Client
Enable Turn Off Multicast Name Resolution policy by changing its value to Enabled

For Linux

vim /etc/systemd/resolved.conf

[Resolve]
DNS=
FallbackDNS=
Domains=
LLMNR=no
MulticastDNS=yes
DNSSEC=allow-downgrade
DNSOverTLS=no
Cache=yes
DNSStubListener=udp
~

reboot

issue happen while renewing Degicert SSL certification , due to some unknown reason exchange took self-sign certificate which results , ECP,OWA, Exchange shell was not able to access and email follow was also interrupted

To resolved the issue below were the action taken :-

1. To Open “ISS Manager”, Type “inetmgr” in “RUN” and select Default Web site and Open “Edit Binding option”
2. Now Select Port “443”.

3. Check the SSL Certificate setting and assigned “Correct Exchange Certificate”      which you have imported with the help of degicert tool

4. Similarly, check for Port “444” Under Exchange Back End Change and View Settings.

444 is for the backed

5. After checking the Configuration of APP pools mentioned in the first restart the IIS services or restart the exchange server.

Thanks 

Error :- 

451 4.4.0 DNS query failed

Cause :- 

Local DNS is unable to resolve the name

workaround :- 

–> Change the DNS from “local to 8.8.8.8

–> restarted the transport service and email flow is working fine

Solution works in my case :- 

–> Restarted the domain controller and exchange

–> revert back from 8.8.8.8 to local

–> check email flow and working fine

Recently Because of ransomware attack I had to build new exchange 2010 server for one of my client, as you know Exchange 2010 is being very known for prerequisites as it required multiple patch and plugs need to install.

I had spend few hours to just find out old patches as it is not available on Microsoft website now

Finally, I have find out one interesting third party web site which is providing the old patch  which may not be available on Microsoft website now.

Download URL: –

https://www.dropbox.com/sh/sdb18dp4kfbbrjs/AABqKBBIGZc6IHYu6H1xK4uya?dl=0 

 http://thehotfixshare.net/board/index.php?act=home 

Here is something which I face today, implemented complete new forest with exchange 2016, since the ADMT migration tool doesn’t completely support Windows server 2016 and complexity of cross forest migration, we have decided for manual migration from old forest (abc.com) to new forest (xyz.com). All the active directory objects are created on new forest with .csv approach and mailbox migration is client driven (from outlook ost to pst migration and pst to ost migration on new mailbox)

Issue: –

Users are unable to reply old email and it was failing with NDR report

Error: –

IMCEAEX-_O=abc_OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+28FYDIBOHF23SPDLT+29_CN=RECIPIENTS_CN=MUSTAN+20ALI775@xyz.com

Remote Server returned ‘550 5.1.11 RESOLVER.ADR.ExRecipNotFound; Recipient not found by Exchange Legacy encapsulated email address lookup’

 Findings: –

• Able to send email after manually selecting email address from GAL
• Successfully able to send email from OWA

Cause: –

• Each email content information of complete path of LegacyExchangeDN form ADSI edit
• old emails LegacyExchangeDN is pointed to old domain

Solution: –

• Since the old domain controller was accessible, I have copy the LegacyExchangeDN information from recipient properties in ADSI edit
• Create X500 record and past old LegacyExchangeDN as email address in new exchange 2016 mailbox email address properties

Manual way to create X500 address (from msexchangeguru) (Link)

We need to add a new X500 address to the user mailbox from Exchange Management Console. To do that, we need to first create it in the right format.

First step is to get rid of the _ and convert them to /

/O=EXCH/OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+28FHSDHJF23GHYED+29/CN=RECIPIENTS/CN=RON+2EMayers@contoso.com

Now the tricky part:

/O=EXCH/OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+28FHSDHJF23GHYED+29/CN=RECIPIENTS/CN=RON+2EMayers@contoso.com

Look closely and you see some numbers like +20, +28 etc… Wondering what they are?

+20 is a SPACE

+28 and +29 are ( and ) respectively

+2E is .

So the actual X500 address to be added will look like this:

/O=EXCH/OU=EXCHANGE ADMINISTRATIVE GROUP (28FHSDHJF23GHYED)/CN=RECIPIENTS/CN=RON.Mayers@contoso.com

Send on Behalf and Send As are similar in fashion. Send on Behalf will allow a user to send as another user while showing the recipient that it was sent from a specific user on behalf of another user. What this means, is that the recipient is cognitive of who actually initiated the sending message, regardless of who it was sent on behalf of. This may not be what you are looking to accomplish. In many cases, you may want to send as another person and you do not want the recipient to be cognitive about who initiated the message. Of course, a possible downside to this, is that if the recipient replies, it may go to a user who did not initiate the sent message and might be confused depending on the circumstances. Send As can be useful in a scenario where you are sending as a mail-enabled distribution group. If someone replies, it will go to that distribution group which ultimately gets sent to every user who is a part of that distribution group. This article will explains how to use both methods.

Send on Behalf

There are three ways to configure Send on Behalf. The first method is by using Outlook Delegates which allows a user to grant another user to Send on Behalf of their mailbox. The second method is having an Exchange Administrator go into the Exchange Management Shell (EMS) and grant a specific user to Send on Behalf of another user. The third and final method is using the Exchange Management Console (EMC).

Outlook Delegates

There are major steps in order to use Outlook Delegates. The first is to select the user and add him as a delegate. You then must share your mailbox to that user.

1. Go to Tools and choose Options
2. Go to the Delegates Tab and click Add
3. Select the user who wish to grant access to and click Add and then Ok

Note: There are more options you can choose from once you select OK after adding that user. Nothing in the next window is necessary to grant send on behalf.

1. When back at the main Outlook window, in the Folder List, choose your mailbox at the root level. This will appear as Mailbox – Full Name
2. Right-click and choose Change Sharing Permissions
3. Click the Add button
4. Select the user who wish to grant access to and click Add and then Ok
5. In the permissions section, you must grant the user at minimum, Non-editing Author.

Exchange Management Shell (EMS)

This is a fairly simple process to complete. It consists of running only the following command and you are finished. The command is as follows:

Set-Mailbox UserMailbox -GrantSendOnBehalfTo UserWhoSends

Exchange Management Console (EMC)

1. Go to Recipient Management and choose Mailbox
2. Choose the mailbox and choose Properties in Action Pane
3. Go to the Mail Flow Settings Tab and choose Delivery Options
4. Click the Add button
5. Select the user who wish to grant access to and click Add and then Ok

Send As

As of Exchange 2007 SP1, there are two ways to configure SendAs. The first method is having an Exchange Administrator go into the Exchange Management Shell (EMS) and grant a specific user to SendAs of another user. The second and final method (added in SP1) is using the Exchange Management Console (EMC).

Exchange Management Shell (EMS)

The first method is to grant a specific user the ability to SendAs as another user. It consists of running only the following command and you are finished. The command is as follows:

Add-ADPermission UserMailbox -ExtendedRights Send-As -user UserWhoSends

Exchange Management Console (EMC)

1. Go to Recipient Management and choose Mailbox
2. Choose the mailbox and choose Manage Send As Permissions in Action Pane
3. Select the user who wish to grant access to and click Add and then Ok

Miscellaneous Information

No “From:” Button

In order for a user to Send on Behalf or Send As another user, their Outlook profile must be configured to show a From: button. By default, Outlook does not show the From: button. In order to configure a user’s Outlook profile to show the From: button:

Replies

If you are sending as another user, the recipient user might reply. By default, Outlook is configured to set the reply address to whoever is configured as the sending address. So if I am user A sending on behalf of user B, the reply address will be set to user B. If you are the user initiating the sending message, you can configure your Outlook profile to manually configure the reply address.

Conflicting Methods

If you are configuring Send on Behalf permissions on the Exchange Server, ensure that the user is not trying to use the Outlook delegates at the same time. Recently, at a client, I was given the task to configure Send As as well as Send on Behalf. As I was configuring Send As on the server, I found out that the client was attempting to use Outlook Delegates at the same time. Send As would not work. Once the user removed the user from Outlook Delegates and removed permissions for that user at the root level of your mailbox that appears as Mailbox – Full Name, Send As began to work. So keep in mind, if you are configuring Send As or Send on Behalf, use only one method for a specific user.

SendAs Disappearing

If you are in a Protected Group, something in Active Directory called SDProp will come by every hour and remove SendAs permissions on users in these protected groups.  What security rights are configured on these security accounts are determined based on what security rights are assigned on the adminSDHolder object which exists in each domain.  The important part for you to remember is that every hour, inheritance on these protected groups will be removed and SendAs will be wiped away.

A good blog article explaining what adminSDHolder and SDprop are and what Protected Groups  is located here.

Source :-  <http://www.shudnow.net/2007/08/12/send-on-behalf-and-send-as/>

To disable circular logging in different version of Exchange Server, perform the following: 

How to Disable circular logging in Exchange 2000 Server and Exchange Server 2003 :

1.       Click Start, point to Programs, point to Microsoft Exchange, and then click System Manager.

2.       Expand Server, right-click the storage group that you want to change, and then click Properties.

3.       In the Properties dialog box, click to clear the Enable Circular Logging check box.

4.       Click OK. When you are prompted to confirm that you want to continue, click Yes.

5.       Restart the Microsoft Exchange Information Store service. To do this, follow these steps:

a.       Click Start, point to Programs, point to Administrative Tools, and then click Services.

b.      In the right pane, click Microsoft Exchange Information Store. Then, click Restart on the Action menu. If you receive a message that other services will also be restarted, click Yes.

Microsoft Technote: support.microsoft.com/kb/314605

How to Disable Circular Logging in Exchange 2007 :

• To use the Exchange Management Console to disable circular logging:

1.      Start the Exchange Management Console.

2.      In the console tree, expand Server Configuration, and then click Mailbox.

3.      In the work pane, right-click the storage group for which you want to enable or disable circular logging, and then click Properties. The <Storage Group Name> Properties dialog box appears.

4.      Clear the Enable circular logging check box.

5.      Click OK.

6.      To make your changes to the circular logging settings effective, Restart the Microsoft Exchange Information Store service, or dismount and then mount all of the databases in the storage group.

• To disable circular logging using Exchange Management Shell, run the following command:

Set-StorageGroup -Identity “First Storage Group” -CircularLoggingEnabled $false

ow to Disable Circular Logging in Exchange 2010 :

• To use the Exchange Management Console to disable circular logging:

1.      In the console tree, navigate to Organization Configuration | Mailbox.

2.      In the result pane, on the Database Management tab, select the database you want to configure.

3.      In the action pane, under the database name, click Properties.

4.      Click on the Maintenance tab

5.      Clear the Enable circular logging check box.

6.      Click OK. 

7.   To make your changes to the circular logging settings effective, Restart the Microsoft Exchange Information Store service, or dismount and then mount all of the databases in the storage group.

• To disable circular logging using Exchange Management Shell, run the following command:

Set-MailboxDatabase -Identity “Database Name” -CircularLoggingEnabled $false