How to Enable POP3 with Exchange 2007

Many users use Exchange as their Mail Server of choice and might not realize that POP3 isn't enabled by default. To enable and start the POP3 Service in Exchange, follow these steps:

1. From the Control Panel go to Administrative Tools then select Services
2. In the list of services, locate and right-click Microsoft Exchange POP3, and then click Properties.
3. On the General tab, under Startup type, select Automatic, and then click Apply.
4. Under Service status, click Start, and then click OK.

Now POP3 is enabled and will start automatically. However some email clients might receive a message stating "Err Command is not valid in this state".

This is meaning that the client is sending authentication in a way that Exchange is not configured to accept. Likely the client is sending in Plain Text. By default Exchange will not allow Plain Text logon. To enable it, follow these steps:

First you will need to open the Exchange Management Shell:

1. Click Start, click Programs, and then click Microsoft Exchange Server 2007.
2. Click Exchange Management Shell.

With the Management Shell open enter in Set-PopSettings -LoginType PlainTextLogin
then you will need to Restart the POP3 service.

Now, Exchange should be able to accept connections from any POP3 client. 

Hope this has been helpful!

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