Setting Up POP3 in Exchange Server 2007

To configure Post Office Protocol version 3 (POP3) in Exchange Server 2007 you need to take several steps on the server as well as the client. This article details steps that are required to configure POP3 service.

Server-Side Configuration
The POP3 service is not started by default in Exchange Server 2007. You need to first configure the POP3 service and make sure that the user is allowed to use POP3 service.

1. Configure POP3 Service
You can use the Services snap-in (services.msc) or the Exchange Management Shell (EMS) to set POP3 service to start automatically. If you are using the EMS then you can run the following two commands to set the service to start automatically and then start the service.
Set-service msExchangePOP3 -startuptype automatic
Start-service -service msExchangePOP3

2. Enable POP3 Access
You configure POP3 on your server by using the Exchange Management Console (EMC).
a) Expand Server Configuration in EMC and then click Client Access.
b) In the work pane on the right-hand side, click the POP3 and IMAP4 tab. If you don’t have this tab then you have not installed Exchange Server 2007 SP1.
c) Double-click POP3 and then configure the options.
d) Click Apply and then click OK.
e) Restart the POP3 service after you make any changes to the configuration.

You can enable or disable POP3 access for individual users by using the Exchange Management Console (EMC), as described below.
a) Expand Recipient Configuration in EMC and then click Mailbox.
b) In the work pane on the right-hand side, double-click the user and click the Mailbox Features tab.
c) Click POP3 and then click Enable.
d) Click Apply and then click OK.
e) Restart the POP3 service after you make any changes to the configuration.

If you want to use EMS, then use the following command to enable the user. Make sure you are using the command in EMS and not at the Command Prompt.
Set-CASMailbox -Identity CAS01 -PopEnabled $true

You can get more information about the Set-CASMailbox cmdlet here. The Set-CASMailbox cmdlet sets client access-related attributes for Exchange ActiveSync, Outlook Web Access, POP3, and IMAP4 for a specified user.

For example, to enable POP3 for user billg@microsoft.com use the following command in EMS:
Set-CASMailbox -identity BillG@microsoft.com -POPEnabled:$true

If you want to enable the change password user interface and also enable POP3, use the following command in EMS for user BillG@microsoft.com:
Set-CASMailbox -identity BillG@microsoft -OWATasksEnabled:$true -POPEnabled:$true

To see all the users that have POP3 enabled use the following command in EMS:
Get-CASMailbox | Select Name,PopEnabled

In addition to the changes mentioned above, you also need to make sure that your Exchange Server is configured for proper authentication. The default selection is SecureLogin, which is the most secure option and it’s best not to change that option. The two additional options are PlainTextLogin and PlainTextAuthentication. TO chagne the default selection, use the set-popsettings –logintype followed by the option you want. For example, to change the default setting of SecureLogin to PlainTextLogin use the following command.

set-popsettings –logintype PlainTextLogin

The PlainTextLogin option allows passwords to be transmitted over the network in plain text and allows connection to the standard (non TLS) port used for POP3, which is 110.

The PlainTextAuthentication options also allows connection to the standard port but it also requires the use of secured passwords. This is configured on the client by selecting the option Secure Password Authentication.

NOTE: Restart the POP3 service after you make any changes to the configuration.

Client-Side Configuration
If you are using SecureLogin, which is the default option, then the server requires secure SSL/TLS connections. For POP3, when using SSL use port 995 for inbound connections and 587 for the outbound connections. In EMC, go to Server Configuration, Hub Transport and double-click the ClientServerName in the work pane on the Receive Connectors tab. Click on the Network tab and you will notice that the port listed is 587. Yes, that’s not a typo.

Rather than using the default port 25 for SMTP communications used between servers, Exchange 2007 uses port 587 which is the standard port for SMTP mail received from the clients . If you double-click the DefaultServerName, you will notice that port listed is 25. I am pointing this out because if you are using Outlook Express 6 or earlier as a client, it can only negotiate explicit TLS over port 25 and therefore you can’t use port 587. A simple solution in that case is to take advantage of the Default receive connector which uses SMTP port 25. In other words, use the following ports when you configure the e-mail clients.

Outlook Express 6 or Earlier

Incoming Mail (POP3): Port 995
Outgoing Mail (SMTP): Port 25

All Other Clients

Incoming Mail (POP3): Port 995
Outgoing Mail (SMTP): Port 587

By the way, everything in this article also applies to IMAP4. The only exception is that when you use SSL, IMAP uses port 993 for incoming mail, instead of 995.

Copyright ©2008 Zubair Alexander. All rights reserved.