Microsoft: Enable IMAP4 or POP3 in Microsoft Exchange

Step 1: Start Microsoft Exchange IMAP4 or POP3 Service
1. Click Start, point to Programs, point to Administrative Tools, and then click Services.
2. To start the Microsoft Exchange IMAP4 service, in the results pane, right-click Microsoft Exchange IMAP4 or POP3, and then click Start.

Step 2: Configure IP Addresses and Ports for POP3 and IMAP4 Access
1. In the console tree of Exchange Management Console ( EMC ), navigate to Server Configuration > Client Access.
2. In the work pane, click the POP3 and IMAP4 tab.
3. Select either POP3 or IMAP4, and then under POP3 or IMAP4, click Properties in the action pane.
4. On the Binding tab, under TLS or Unencrypted Connections, click Add.
5. On the TLS or Unencrypted Connection Settings page, under IP address to Use, do one of the following:
    a. To use all available IP addresses for a server, select Use all IP addresses available on this server.
    b. To manually specify an address, select Specify an IP address, and then enter an IP address in the dialog box.
6. Under Port to Use, in the box next to Port, enter a port number, or accept the default port.
7. Click OK to save your changes.

* Note: Make sure you have allowed the specified IMAP4 port at the firewall.